In practice I get a lot of value out of referencing commit hashes. If I fix a problem I introduced in a previous commit (for example, commit bumped version, and I forgot to bump it somewhere), my fix will say "amends ab12cd34".

That way when I need to cherry-pick that commit, or do something similar (bump again), I can search for the hash of the commit I'm looking at to find what might be missing.

UI is worse than git-notes but no need for additional setup to sync them.