Not GP. My guess is that they’re self hosting this at home (not on a server that’s on the internet), and Tailscale easily and securely allows them to access this when they’re elsewhere.

Even if you are self hosting in the cloud or on a rented box, Tailscale is still really nice from a security perspective. No need to expose anything to the internet, and you can easily mix and match remotely hosted and home servers since they all are on the same Tailnet.