There are places you could use it I guess, sort of like our recent pickle juice discussion. But it's not a bold flavor and I think it has a sliminess I'd be reticent to add to my food. My point about bold flavors is that they're more interesting in the small amounts you add because of all the salt and acid these canned liquids contain. But for commercially roasted peppers, there's just not enough going on with the flavor to make it worthwhile.
I'd rather use a fresh or roasted garlic than a pickled one for my preferences.