Well you could if you have a line-unfeed. So by default it would do both but then in the uncommon case where you want overtype you could go back up.

A little late for that insight, if its even worthwhile, but typically I would optimize the common case by default and add features for doing advanced / uncommon things.

That has always been my understanding. If you want bold, underline or strikethrough then you need to be able to send a carriage return on its own.

You could just backspace repeatedly, but it'd be a waste of bits.