But that's what I'm getting at. Even if it is much more, is all of that immediately relevant to a curious/potential new user?

I understand it may not be easy to narrow down the explanation, especially if you invested a lot of time and don't want to do a disservice to yourself by underselling it. Looking at the Tailscale tagline I quoted, it is small and ambiguous enough that it works marketing wise, regardless of all the features and solutions they offer. But it was just an example, I should maybe have used a totally different example of a product that is not in the same realm as yours.

The explanation you gave to me here is good but only because I vaguely know what all this jargon means. Try to think of a short simple sentence that a non-expert could understand.