Why are NS records automatically created when adding a domain to your account?

As described in a previous question/answer NS records are available to delegate subdomain hostname resolution to other/non DO nameservers.

The desired action of adding one’s domain to DO’s name servers so it can be found is complete. Are the NS records doing something pertinent to that process?

I notice when I delete the three NS records my domain now says ‘multiple locations’ under Directs To on the Networking page. I can make some assumptions about what those NS records are doing for DO (or the web portal specifically) but I’d appreciate some clarity. I’m no networking guru, obviously, and I’m trying to keep my Networking records as clean, clear and minimal as possible. Why are the NS records automatically added if they’re only for delegation, or are they doing more?

Thank you for any help on this