Few of them for most use cases, especially a VPS. My server have a couple of IPs each mapping to a different VM, they can all claim 22/80/443 as you’d expect, but that’s just basically the same as having a bunch of VPSes anyway.

It’s useful for some other uses like, I might want to dedicate an IP for VPN exit that doesn’t expose any services.

Another use is sometimes you just want two things to stay entirely separate, even if on a technical level it could work with a reverse proxy. It can eliminate some class of exploits like request smuggling.

One use case I’ve had for a customer is they have a system that can only do TLSv1.0, which is wildly obsolete and exploitable. So that particular API endpoint was served from a secondary IP, that way I can continue to enforce TLSv1.2+ on the primary IP. It’s possible with some reverse proxy magic with HAproxy, but I could also just make a new server block in the existing NGINX bound to that IP and call it a day.