(a) They use network bandwidth, not much CPU power. So when you install it, you'rer sucking up some of the Internet capacity. I would call that a "bad".
(b) Me, I'd prefer donating to cancer research (I think there's one of them out there) or SETI than whatever payments I'd get out of CapCal, assuming they actually do pay and that's not something they say to lure people in.