It's not about optimizing, it's about not doing additional work just to break the expected behavior of the web platform. So far there was no explanation of where default behavior breaks keyboard usage, for example, only opinions.
I meant optimizing every possible usecase. Did you know the button on this very site is not selectable? When you use real semantic html with submit inputs, not buttons, there is text that is not selectable. But it is a button? See what I mean? Draw the line somewhere.
