While copying puts something to the clipboard, pasting does nothing. Found a bug?
3.3.1 (3343)
Yes, I think pasting number values is a good idea.
The number value rows are synced between masters already (the rows only, not their values), so they behave slightly differently to the other rows in the Masters panel. That is complicating copy-pasting number values between masters, but it should probably still be doable.