

Can you explain the Ethernet requirement more? Was that just that the computer didn’t have WiFi, or was it set up such that only the wired interface worked with their VPN, or…?
Can you explain your travel router situation? Did you use the travel router to access WiFi and provide an Ethernet port for the computer (I think this is called “WISP mode”)? Or was this an 4G/5G router?
In any event, at least on Android you can connect to WiFi and tether to a computer over USB. It’s very useful for setting up a computer without WiFi drivers, as Linux will almost always recognize the shared Internet (so, it’s functionally a USB wifi dongle with very good driver support).
I think a lot of companies view their free plan as recruiting/advertising — if you use TailScale personally and have a great experience then you’ll bring in business by advocating for it at work.
Of course it could go either way, and I don’t rely on TailScale (it’s my “backup” VPN to my home network)… we’ll see, I guess.