The whole Tailscale experience for an enduser (ie not Tailscale admin) is so much nicer than compared with something like OpenVPN in a place without MDM.
to be fair, their mobile UX has plenty of warts and behaviors that don't match platform expectations and are confusing (like what happens when you tap on any of the listed machines that you have access to).
This one seems to at least have been partially motivated by making sure that accessing tailscale without paying is not too visible.
I'm saying this as a huge fan (and paying customer) of tailscale.
Not sure what this means, Tailscale is free for the vast majority of non-corporate users, and I would imagine that anyone who's using it so intensely that they need the "personal pro" plan is probably someone techie enough to dig around and find out about headscale.
Also headscale isn't entirely free if you're paying for a VPS or other server to host it on.
An extra field in an "Advanced Settings" menu should not need to be hidden behind some "Press About 5 times" secret gauntlet. Users are not so stupid that they will fill out an "Advanced" form field they don't understand, and even if they do, you can always make a connection attempt to see if the input was valid.