Complicates development-code distribution: When a user checks out a new revision of the source code from git, the changes won't immediately have any effect, unlike (most) changes from non-transpiled modules. Instead they have to be sure to run npm run-script prepublish
to recompile.
Actual user conversation from chatroom (lightly edited for relevance):
developer Jan 24 15:33 update, I fixed that recently
user Jan 24 15:33 ooooohhh, ummm
the current [module] has that update, or do I need a special fork version from you?
other-developer Jan 24 15:35 It was merged yeah