Aside from bashing a paradigm one is not used to/doesn’t like/didn’t grow up with, what are the real cases where dealing with the textual output of procfs creat

Aside from bashing a paradigm one is not used to/doesn’t like/didn’t grow up with, what are the real cases where dealing with the textual output of procfs creates serious realistic performance issues? The argument about insecurity of a hand rolled C parser for that is utterly unconvincing.