I think that rim wear "on the fly" is not a huge CON to rim brakes. Rims are parts that need to be checked one in a while and they don't wear out suddently.

Another advantage of disc brakes: overheating is more expensive but less critical.
If you overheat your disc brakes, the disc overheats and warps; to solve the problem, you usually need to replace your disc. In extreme cases, if that happens on the road, you'll need replacement parts before you continue. ($$)
If you overheat your rim brakes, the rim overheats a wee bit so it doesn't warp. However, the tire gets warmer and explodes. As overheating usually happens in a downhill, you're riding at high speed, so you are more than likely to fall. So while the repair might cost you only a patch, your bodily repair will cost more.

BTW, this is a problem with heavily laden tandems in the mountains.