Shel, to me, the difference is in how you work the peppercorns.
For 'cracked', I use an old mortar and pestle, for ground, I use a peper mill.
One difference is when I 'crack' the peppercorns, you get a much more intense flavor than when using the pepper mill. I use 'cracked' when I make a rub with pepper, brown sugar and garlic to pack on top of a pork loin. I use ground pepper from a mill for a salad.