Linda's post is a good one.
The rise in biscuits comes, one way or another, from gas in the dough. The reason buttermilk is "traditional" with biscuits is that baking powder is a relatively recent invention. In the days before BP, biscuit makers used baking soda as the leavening agent (ever heard of soda biscuits?); and an acidic liquid was required to make it produce carbon dioxide.
The carbon dioxide lightens the dough by riddling it with bubbles. Even after the gas dissipates and is replaced by air the dough remains light as long as the dough has its bubble structure. When the dough is baked, the air in the bubbles expands and makes the biscuits rise.
Baking powder uses soda itself or something like soda plus a dry acid as one of its two (single acting) or three (double acting) active ingredients. That means that "non-traditional" liquids like regular milk, cream or condensed milk get (almost) as much rise, and allows the baker to play with different flavor profiles not to mention a range of milk solids to butter fat ratios.
It's interesting that Linda pointed to cream as one of her favorites and powdered milk (which is non-fat) as the other.
Single acting BPs get all their rise as soon as they get wet. That means, that just like soda biscuits, bakers have to be very careful to protect the bubble structure by getting it in the oven fast -- before it has a chance to fall; and by not over-handling the dough and pushing those bubbles out.
Double acting BPs do that, plus they have another leavening agent that doesn't go to work until it;s heated. So, with double acting BP some of the gas production comes in the oven. That gives the baker a little leeway with time and handling -- but not much.
So how do you make BP work its best? First, you use the right amount. If you look at the biscuit recipes in this thread, or on this site, or read A LOT of cookbooks, or survey the web, you'll see that the ratios of necessary ingredients in most yeastless recipes are almost always the same. For each cup of flour: Slightly 1/3 to 1/2 cup of dairy; 1-1/2 tbs to 2 tbs solid fat; 1 to 1-1/4 tsp BP; plus a pinch of soda. Sometimes other ingredients like sugar, cheese, salt, herbs, etc., are added -- but they're all about flavor and have little to do with biscuits' essence.
And yes, there are some recipes that move the proportions of one ingredient (almost always the fat) outside the usual ranges, but they're outliers.
If most recipes are pretty much the same, the big difference must be "the baker's touch," Linda talked about. Well, yes. Or, better, well YES! The thing of it is, that is it's not that hard to learn 90% of it.
First: Measure and mix your fairly well. You don't have to sift, you don't have to weigh, you don't have to overfill then carefully wipe the tops of your cups and spoons. You have to be close. There's something counterproductive about being too accurate.
Second: Work the fat in well. Most recipes talk about "coarse meal," which has most cooks looking at the size of the lumps. Fine. More or less evenly sized lumps is a good thing -- but not the most important thing. You must make sure that there's no unincorporated fine grains of flour at the bottom of the ball. All of it must be "stuck" to little globs of fat.
Third, Fourth, and Fifth: Don't trust your measuring cup with the liquid. The liquid must be incorporated as quickly and as gently as possible. The amount of moisture in your flour varies with humidity -- quite a bit. That's why there's no perfect recipe. Measure your liquid in an amount the recipe calls for, plus a little more. Pour in about 2/3 of what's called for and mix with a few quick strokes. If the dough doesn't come together completely, add so you've got the recipe amount, and mix -- again with a few quick strokes. And so on, until the dough comes together. Don't worry about getting too much liquid in. Biscuit dough should be wet.
Sixth: Don't waste time, work the dough as quickly as possible. Some of which mean going back in time. Have your bench (board) floured and ready. Have extra bench flour standing by. Have your pin pre-floured. Have your cutter pre-floured.
Seventh: Work the dough as gently as possible. This is the "touch" stuff. What all the stuff has done is get as much bubble structure into the dough as possible. You want to keep it. When you take the dough out of the bowl, it will feel light for its size. The more you work it, the longer you take, the denser and heavier it will feel. You're probably reading the key words as "work" and "longer." Nope. "Feel." The dough will tell you what's going on with it. As soon as it starts to feel dense, heavy or stiff, quit fooling around.
Recipes talk about things like "10 kneading strokes," in an attempt to provide sure guidance to cooks who aren't familiar with the process. But, just like exactly measuring the liquid, you have to let that go in favor of what's actually happening.
As soon as the dough comes together get it out of the bowl and onto a pile of bench flour. Dust the top. Turn the flour over a few times so it's well coated with dry flour. Knead very gently until the dough doesn't feel incredibly sticky any more. How do you know? It only clings to your hands a little bit. Subtle? Not particularly.
Don't waste time. Wash and dry your hands, flour the dough on both sides again, and shape it into a miniature of the shape you like to cut. Then roll it or pat it out. If you use a pin, a plain pin works best. That is, no handles no ball bearings. You want feel, not power.
NOTE: I "turn" biscuit dough the same way one turns puff pastry, i.e., by folding and rolling, re-folding and rolling. But my biscuits are still light. Why? Partly because I do it quickly and gently. Mostly, I stop when the dough's texture changes. I might feel it when I pick up an edge to make a fold; or I might even feel it under the pin. The difference in feel isn't subtle. If you're looking for it, you'll feel it too. Now, I'm not recommending that you turn your biscuits too. What I'm saying is trust the "feel." It will tell you exactly how much with which you can't get away.