Why Not Beat Them First?
I've probably made hundreds of pancakes and waffles over the years and I've certainly baked dozens of cakes. Many of the recipes I've used, if not most, call for separating the eggs so the whites can be whipped until firm and folded in at the end to give the batter a lovely lift. Recipes generally go like this: First you combine the dry ingredients, then the wet ones, then the two mixtures together. Finally, you beat the whites, which-unless you have multiple beaters-involves thoroughly washing and drying your beaters before proceeding.
Call me lazy, but I think recipes should call for beating the whites at the get-go, not last; it's not as if they'll deflate in the three to five minutes it takes to assemble a batter. It's simply formulaic recipe-speak as far as I'm concerned (and yes, we here are just as guilty as everyone else).