IMHO, OCaml's decision to not encode strings in a Unicode encoding by default is the correct one. OCaml treats strings as just bytestrings, leaving the programmer to take care of the specific encoding, with the help of sophisticated and powerful libraries like Camomile.

For an example of what happens when language implementations try to shoehorn in Unicode into their strings, look at JavaScript's UTF-16 strings or this Python example: https://www.reddit.com/r/programming/comments/asi2qo/go_is_a...

Compared to my experience with Python 3 and Ruby, OCaml is so much better. On the rare occasions I need to do something Unicode-y, I'll reach for Camomile, and the rest of the time I'm passing around strings/bytes unimpeded by silly language decisions.

OCaml's decision is more to leave unicode support to libraries rather than let compiler writers handle unicode support as a side dish.