"try before you buy" (have personally never seen anyone do this). i guess my rants on tig prompted some people to give me some justifications i can accept as legit, so thanks for that.
I did this for half of my old steam catalog. Half life, dawn of war, dark souls 1, starcraft 1, diablo, torchlight, etc etc etc.
Admittedly, nowadays steam is evcen more convenient than pirating, so i dont bother much anymore. Im considering it doing it again because of what others have mentioned - I have had blur, sants row 2 and 3, ruse, and many other simply not fucking run on my rig, and now they clutter my already huge steam catalog.