IMO, yes, calories matter, but not like they do in high carb. In high carb, calories matter a heck of a lot more, I think.

Here, because of ketosis, we're peeing out all sorts of excess calories in the form of ketones. That amounts to (I read somewhere on this board) up to 300 calories a day. Could be none, too, but potentially some calories are being wasted every day. Sounds like a bit of a metabolic advantage to me.