This is about unprivileged users - privileged ones can see everything. The idea is to make figuring out what's the surface of the attack harder (for those attackers who are less than skilled) by making it less obvious that 10 years old game server process is running on this OS.

The sysctls affect all non-root users. If you have them set, you have to do all the admin work as root.

If you have them unset, you can login to the server as you, see what your service user is up to, and only have to do interventions as the service user or root depending.

If you don't want your service to see what else is going on on the server, you can put it in a jail and not allow jailed processes to see out; not a bad idea to do that anyway, although it does mean starting the service needs root when it likely wouldn't otherwise (you can drop the high priviledged port to 79 and then your service can listen on port 80 without root)