They are annoying, for sure.

Some of them appear to be an attempt to be helpful to new users, without having to manually monitor for new accounts and type up or copy/paste a welcome message, but it's way too overwhelming, especially if they are new to both Nostr and Bitcoin.

They are trying to head-off the inevitable AskNostr questions that will be asked and answered over, and over, and over. But that's the thing. People need to progress to the point where those questions are important to them, rather than have them answered out-the-gate when they have no idea why they might want them answered yet.