It's really not arguing just to argue. What you're talking about is just timezones with extra steps, so why not stick to having a time zone?
Right now, I'm GMT-5, and if I'm scheduling something, I can look in their slack profile and see that they're GMT-8, and adjust accordingly. If we get rid of timezones, I have to know where they are, and what normal working hours are where that is. The simplest way to do that is a big table of offsets from some standard starting point, which is exactly what a time zone is.