There's no need to wear or even carry a MB with you to use as a "ticket" or for FP+
or for opening your WDW resort room door or for charging your various purchases.
Just request a standard plastic RFID ticket, which will work in place of the MB for all of the above.

this. I personally don't care for the tracking when using the bands, so I just got the card. Some CMs were confused that I didn't have a band, but I just didn't want it and truthfully, I never missed it.