Global UI? You mean, AWS-hosted configurator for your network? We just had example of it being security risk. God save Mikrotik from implementing something similar.
I think it's specific to Access Points, so not a general purpose centralized controller for MikroTik equipment, but... centralizing access point management seems to be the main thing under discussion here.
No, you don't? I mean you can but you don't need to.
There are cases when that is useful, true - for example, the automatic channel selection makes some curious choices sometimes.