Likely because one would “applaud the effort”. If I can’t prove to the interviewer that I’m capable of going beyond leetcode, by building my own language to solve the same problem, then I might as well memorize a thousand solutions to cheat my way into FAANG. The latter will guarantee entrance, but I can’t stand the memorization process. I’m a professional, and like an undergrad or grad, I shouldn’t have to memorize homework problems to pass exams

> when I'd imagine the skills for creating a programming language have limited overlap with Leetcoding.

FWIW golfing languages are a thing, where a language is designed specifically for code golfing type problems and usually optimizing for a tiny core language and small source files.