Noon is midday. It can't be 2pm somewhere where it isn't 2 hours past midday. You could use the 24h system with UTC everywhere, but that's already done for any systems that need synchronization.

We don't use it in day to day life, because for 99% of people, only one timezone is relevant at a time, and keeping the meaning of different times the same takes precedence.

Also useful is knowing what the average person is doing in a country you're interacting with. If I message my coworkers in Romania (arbitrary country, I have coworkers there) at their midnight, I know I won't get an answer till their morning. If it just says 15:00 or whatever on the clock and there's no timezones, I would have to put in significantly more effort into figuring out if people in Romania are sleeping now.