Localhost development has always been a pain. You might use ngrok to expose your server securely so that you can check it on a different device. Or, you might want to test an ingress or a complex constellation of services. Services always require so much different configuration between dev and prod that bugs easily sneak through.
Thanks to WireGuard, VPNs are easier than ever to configure. Using a service like Tailscale lets you access all of your devices with magic DNS. This means you can forget about Dynamic DNS services to route SSH tunnels, and manage connectivity much easier. Also gone are the days of complicated VPN setup and debugging networks and overlays – WireGuard is (relatively) dead simple.
Personally, I've started to use a VPN between my workstation, laptop, and mobile devices. I could imagine it starting to be useful for hybrid development – running some services locally and others in the cloud. Of course, this whole setup could be leapfrogged once we move to remote development.