Something pops out and blinks on itself while you are typing. At least that's what I've seen in neovim "ads" videos back in the day.

Very annoying. I decided to move from manually creating my own config to using Astronvim and there were just so many distracting things in the default installation. The good thing is that you can disable what you don't want - which I did. The bad thing is that finding the right option or the actual plugin that is bringing the functionality you don't want takes some time.

Was the prebuilt configuration worth it in the end then? I recently started a from-scratch config and followed kickstart, which is pretty minimal and also not a plugin/distribution/self-updating thing, it’s just an example config file you can copy.

Yeah. Once you understand the configuration it's really nice, it is also well documented.

A good option is to start with kickstart.nvim. This allows you to build up from a very basic install, or keep the simple default install without a lot of plugins.