Reason seems to be pretty dead so now the relationship between ocaml and rescript is kind of like that between haskell and purescript.
This may be good if you only want to run it on the frontend but it's not as good if you're using ocaml on the backend and want to share code, but I guess there's js_of_ocaml
I also don't think the existence of rescript is in itself a bad thing, it's just that the whole confusion around reason/rescript may have harmed development of ocaml for a while.