Re: Why, in the name of all that's holy
I don't think your average gas fitter or consumer would know how to open ports on the router, so I don't think that's a (commercially) practical option. The server approach would be vulnerable to server failures regardless of how things were working.
I agree, though, that more autonomy would be better, so 'no server' means 'carry on as normal'. Does it not work that way? Ours is under manual control (no timers), so we didn't see much difference.