I would have loved this at a company a couple of years ago which was massively all in on Google Auth for literally everything. If you're fine with that being your concrete level of authentication for everything; internal tools, external tools, etc, then tailscale sort of just slots right in, and SSH makes it even more so.

I would be very hesitant to build around this personally, hijacking Google accounts is already something pretty high value to a companies adversary, and using Tailscale and SSH like this turns it from a compromise of accounts indirectly through password resets into access to unlimited production machines, internal services, etc. It feels almost layer violating to have a soft social login through Google, that gets persisted in every Chrome browser and logged into on every employees phones also directly control SSH, but maybe that's just me.