Time zones aren't just so everyone on the planet can start work at 09:00 local time. They're also for snapping everyone in a region to a shared time, even if it's a little off from their solar time.
Check out the history of railway time for the birth of time zones: https://en.wikipedia.org/wiki/Railway_time
For this one, It really amuses me on how they think they would accomplish keeping someone's phone to alarm at the equivalent of 7am when they fly across a nation.
Granted, I still hold the silly view that we should probably change daylight savings time to be a 10 minute change of the clock every month. Up for six months, down for 6 months. Would effectively be trying to tie it to actual solar time, which is what we seem to care about. And would be trivial with modern devices. (Though, no, I don't hold that this will happen.)
Amusingly, these difficulties aren't static, either. Easy to argue that before rail and modern time pieces, what you are talking about is exactly what happened when people were using solar clocks.
And again, it's a weird inversion in the role of a machine. Machines should make life easier for us, not the opposite.
What about, say, Amsterdam and Stockholm?
