i personally have used it
* to provide access to my home network, as though i am on the home network, while outside of said network
* to connect several locations to the same business network
the first lets me provide locally hosted services without exposing them to the internet, by allowing members of the VPN ("tailnet" in their parlance) to connect to those services
the second was very handy to move a few users from a company in the process of shutting down to their homes, so they could continue to work like they had in the company network once the actual internal company network was shut down.
Quite legitimate, a common use case of VPNs, an L3 encryption tunnel to provide virtual LAN access. It's kind of a hack usually, but it might work as a second redundant layer of security (the other usually being HTTPs, and in the case of there being no other layer of encryption that's where VPN wrapping is kind of a hacky solution).
The other common but completely distinct usecase of VPNs being residential usage to encrypt traffic and even more distinct, with the purpose of masking the true origin of a request.
In the former type of usage, which is the one you use, I think any VPN system would fulfill your purposes, of course you have to use something, but I'd venture a guess that you are using the generic features of tailscale, not its commercially distinguishing features. But they are still very on brand, generic or not.
fwiw, the author/founder seems to have made a career out of building post-hoc hacks in one layer to fix the shortcoming of other layers, to take memcached as an example. I don't think my thesis is novel, that these types of hacks are subpar when compared to solving the issue at the appropriate layer, it's part of the tradeoff of the technologies, but I'm just particulary opposed to any hack that allows server admins to skip the step where they get a dedicated IP address, I'm less opposed (but still) to other types of hacks.
This isn't due to tailscale not supporting or working with netcat; you can nc to an address on your tailnet just fine.
This is using the infrastructure tailscale set up for a different purpose. Rather than requiring a tailnet or even an account anywhere, you can tailcat between any two endpoint. Tailscale is there because it runs the DERP relays which get the client's pubkey to the server, brokers the connection, and coordinates holepunching.
the first lets me provide locally hosted services without exposing them to the internet, by allowing members of the VPN ("tailnet" in their parlance) to connect to those services
the second was very handy to move a few users from a company in the process of shutting down to their homes, so they could continue to work like they had in the company network once the actual internal company network was shut down.