Please use the search - lot of issues have been discussed already. Your request is very specific maybe generic search engine gives you more background about the protocols.
The implementation at the moment is designed in a way you need this to be active (or accept configuration warnings).
I have searched and that’s why I am asking, I didn’t find what I was looking for.
I know what the nodeinfo and webfinger protocols do and since I don’t have any apps active which (at least by my logic) would need them, I am confused about why nextcloud wants these.
Since also searching these forums didn’t provide a solution (only people who ask about how to set it up), I decided to ask.
I can’t say for sure but for me it looks like this protocols could act as foundation for many Nextcloud functions e.g. federated sharing, OpenId authentication and others. Looks like the devs decided this are important enough to make them mandatory.