Waffle batter normally has baking powder in it to cause it to rise, or the egg whites in it have been whipped to make it fluffy.
Bay biscuits… probably don’t have as much baking powder in them as they’re pretty dense when you dollop out the dough and they don’t rise much in the oven.
So while you can make fluffy things in a waffle iron, just because you make bay biscuits in a waffle iron doesn’t mean they’re going to be fluffy.