We always wear our buttons, it just makes the day more special. Lots of CM and other guest saying Happy birthday, Happy anniversary, or Congrat's.
Its also sort of an ice breaker, if you are doing family style seating like in Germany, or sharing a table at a quick serve or picnic table at one of the water parks and of course waiting in line which you do a lot of.
We have gotten a few cupcakes and other desserts at TS restaurants, some cards with the Fab 5 and other character signature, a CM sang happy birthday to my mom outside of Soarin, and the crowd watching joined in, it was her 70th birthday, so added pixie dust...
Its fun wearing your button, it makes you feel special.. on your special day, really that's what its all about..