This is also true of "its in the repo" and that doesn't get hit by "find and replace".
I don't think it should be done for EVERY case, rather the cases where clarity is replaced with something that is ambiguous but meets another need. Performance hacks are notorious for being "ugly" and "magical" and having a readable companion piece would make sense.
To clarify I don't think it replaces "prose" but should exist along side it, and be mixed into it.
It's very much not! The thing "in the repo" is of exactly the same vintage as the thing in the next commit. The thing "in the comments" is preserved in amber next to a growing thing that no longer matches it. Inevitably to understand the thing "in the comments" you have to go back to commits of the same age.