Well, sometimes you are in Do not Disturb mode, so notifications don't come through. Also, this thing would always be on, and you simply need to glance over to see:
Next meeting in X minutes. Also my calendar is kinda full, so seeing conflicts for the next meetings would be super-cool.
...so let me get this straight. You've specifically told your computer not to remind you about meetings in the straight-forward built-in way it can, and want to build a separate overengineered reminder system out of an overpowered toy to do the same thing?
Christ. No wonder everything in our industry sucks.