Wireless game controller - polling vs events
I think you should make a difference between 'scanning' the buttons and sending them.

Scanning I would do very fast, as you say, you cannot press them faster than 10 ms, but maybe others can so maybe you need even a faster scan.

For sending (wirelessly), you can send them only when changed (as long as you know the receiver received it with some return message/confirmation). If there is no confirmation you can send it often (and a missed message will be overwritten some ms later by the latest update).