I'll just pop in to say I am working on an app & a widget where testing different times/days/time zones/DST or not is vital. And of course you still can't do this in the sim.
Widget for sun/moon event times. difficult to fully test, especially when chasing down a time of day bugs.
My point is, why disable it when it's built into the sim already. Just because you and Garmin can't image a reason to need it does mean they should disable it.