The problem with using findall instead of finditer or search is that it scans the whole document rather than just until the first match, and it builds a potentially huge list just to throw it away. It’s pretty common that one or both of those will be a serious performance issue. Imagine asking to find the first double consonant in the OED and it takes a minute to run and pins a gigabyte of memory.

It’s unfortunate that these functions aren’t better matched. Why is there a simple-semantics find-everything and a match-semantics find-iteratively and find-one? But I don’t think adding a simple-semantics find-one that works by inefficiently finding all is the right solution.

And if the point of proposing first is that novices will figure out how to write first(findall(…)) so we don’t need to add findfirst, then I think we need findfirst even more, because novices shouldn’t learn that bad idea.