> There was some discussion around ⏾ as several “moon” characters already existed. None of them [...] convey the semantic meaning of “Sleep” – so ⏾ was accepted.

I'm not convinced ⏾ conveys that meaning either, unless it's explicitly used alongside the other new symbols. And if it is used alongside those symbols, a couple of the existing moons could also work just fine.

(⏾ is appearing as tofu on HN for me, but I'm just going to roll with it.)