> Yeah, but to the extent that the server is useful, it needs to be exposed to the internet.

Not if it's a private server, like the poster above was describing. For example, if I want to maintain a NAS to store my photos and view them anytime, I am better off running it on a Tailscale network that only I (and some friends/family) can acces, no reason to expose it publicly and then try to secure it.