At this point in time pirating is much more of a hassle than buying games, especially considering healthy sales are almost non stop for pc.
Also true. Why should I bother pirating? The really old games usually cost next to nothing, the rest goes on crazy discounts every other months. Oh, and there are also refunds. Maybe the new releases, but then I'd run into the problem with the game getting a new patch every week and the pirated version would go unupdated, so again the convenience problem from the previous point about using Galaxy, I'm way too lazy to manually download and apply patches if Galaxy or Steam does it for me, I'm for sure too lazy to track down and download a pirated copy of a new version of the game every time a new patch comes out, that's just not happening.
It really only makes sense for games that are just not available anywhere, but then I wouldn't even consider it piracy, even if it technically is.
edit: maybe also for games with really annoying DRM that makes the legit copy worse to play than a pirated one, but I can't say I've ever run into that problem.