If you use the correct brake blocks, carbon rims don't wear much at all compared to alloy rims.
firstly the block compound is softer, so the block wears rather than the rim
secondly, what tends to wear alloy rims more quickly is little bit of alloy transferring from rim to brake block and thus wearing the rim. That doesn't happen with a a carbon rim.
That said, like
@Webbo2, I try not to use that bike in the wet