Ok, now I remember why I'm not using Lists in Mastodon: List management is barely functional.
Getting there needs several clicks. I can't just add someone to an existing List from their profile (or a post). I've managed to mix up the List name and search fields several times now (and then wonder why the List name has changed). I can only search for account names, not for domains. List management is a modal, and I need a second Mastodon window if I want to search for people to add.