Is it, though? I find it far easier and faster to click on field, type username vs. look at field, see username is incorrect, click on the field, highlight/back

Is it, though? I find it far easier and faster to click on field, type username vs. look at field, see username is incorrect, click on the field, highlight/backspace to select, re-type part of the username. If I've gotten my username wrong, it's usually because I made a typo, in which case, re-typing it will solve the issue, or because I simply don't remember it, in which case, seeing what I typed previously isn't really going to help with that.