cause they seem like perfectly integrated themselves into this, while ntfy has to pose itself as battery consuming application

I'm planning to using ntfy for notifications like bitwarden vault backups, if apps are updated.

The difference: Your phone doesn't get notifications from your notification service directly, but from Mozilla which helps to hide your digital fingerprint of you using a separate notification provider like ntfy. Prism also allows Telegram or Signal to act as a notification distributor. In addition, I use Proton Mail which doesn't really allow custom notification services. Prism has a custom integration to work around that so your proton mail notifications don't have to touch google services.