The selling point of Tailscale is that they simplify Wireguard UX by adding a proprietary control server - this adds complexity to the stack (extra component) but simplifies user experience (Tailscale run the control server for you).
Headscale seems like it's complicating the stack (adding an extra component) as well as complicating the user experience (you have to maintain two components yourself now instead of just the one Wireguard instance).
Granted I presume the Headscale control server might simplify management of your Wireguard instance but... you're still maintaining the control server yourself.
I was speaking more to doing it all in-house, versus outsourcing things to Tailscale, a third party not fully under one’s control, even if they act of behalf of the user. I think I largely agree with what you said.
Buying hardware is an investment (& not something everyone can do) but I've really never understood the point of the control server from the perspective of an open-source self-hoster (for a business like Tailscale it makes sense as it introduces an element of control, user dependency & likely analytics of some value).
There's still a lot that can be done to improve Wireguard's UX but I think the Asus example proves it can be done well. Headscale seems to be doing the worst of both worlds (promoting an architecture & user-flow of a proprietary closed-source competitor, while still requiring CLI setup & instance maintenance). For example, it seems to me like it would be better for them to wrap Wireguard directly & integrate with the actual Wireguard mobile app instead of having people install proprietary Tailscale app on their phones to use your own open-source self-hosted control server.
