I've used them, and now I have the brev-dev mailing list that @firstname.lastname@example.org set up. But mailing lists still require micromanaging, just like @nergal
said, people who mess up how to subscribe and unsubscribe or post properly etc. Mailing list modes on other apps is probably the solution, like how Lobste.rs
And mailing lists still have the room model which has some pros and cons compared to the follow/friend model of mainstream socials.
Another awesome thing for mailing list lovers is @delta
groups, both verified groups and plain. They work with, and abstract, the convention of normal people (huge CC-lists) as opposed to fighting human nature. I love them, I have a ton of groups on there. If I can't all my friends in the same room, at least I can have a ton of hyperspecific rooms with a lot of overlap. ♥