Tailnet and Magic DNS make it easy to bring other people or devices to your network, including simple authentication mechanisms to know who is who
A VPN is literally a… (Very) Private Network.
Virtual, not Very
Woops! This is what sleep deprivation does. Thanks!
That doesn't contradict anything I said. Private networks can be huge, e.g. in big companies, and they can still use .internal. .internal serves quite a different purpose to that proposed for .self, so the top level comment I replied to doesn't make much sense.