Vanilla's /help command would normally show all commands to OPs, but only show the 4 commands available to non-ops (/help, /me, /tell, /trigger)

In spigot, /minecraft:help will show all vanilla commands available to non-ops, despite them not being expected to be able to use them as they are not OP'd.

I wouldn't expect /help to be permissions-aware, just OP-aware as per vanilla.