I've heard both ways on this, and I do know for a fact that they matter
a lot to at least some controllers. Seems to me that they certainly
ought to - these are the official demarcations of the runway, right, and
*part* of the responsibility of controllers is to enforce the FARs (to
report violations of) at the facilities at which they work (not that I
want them to persecute pilots, of course).

Actually it wouldn't have been. In order for you to be on the runway,
from the controllers point of view, you have to cross the white edge
line on the runway. The hold short lines don't determine anything for a
controller.