NuffCatnip: Out of convinience ?
With some old CD/DVD based games yes definitely. In particular most of the old Tom Clancy games because the copy protection built into them sucks ass and tries to tell me my game is not an authentic copy and the official Ubisoft workaround is to disable DMA on the DVD drive and slow down all CD/DVD access to a crawl just to make their copy protection happy. If I eject the disk, click the mouse to start the game and then push the disk in sometimes that satisfies the copy protection. Eventually I get sick of that bullshit and just download a crack for it. That's for single-player only gaming. If I'm playing multiplayer however then I always have to install a crack because Ubisoft says the CD key is invalid for every single game because pirates have written key generators that eventually collide with people's legitimate store bought keys and Ubisoft happily invalidates the keys that legit customers bought and they don't give a shit about it and expect you to go buy a new copy of the game which also has an already invalidated key before you even open the shrink wrap. They'll tell you to keep your keys safe so that someone else doesn't see it over your shoulder or whatnot, instead of owning up to their DRM sucking ass, and their method of dealing with pirated keys harms their legit customers.
So... I crack that shit as it's the only way to play the game other than using LAN mode over Hamachi with added lag on games that support it.
With some other games I use a NoCD crack if the game doesn't have a built in way to do noCD and putting the CD in is a huge annoying PITA, although some games have a hidden command line switch to the game EXE, or some other mechanism to do it like Starcraft which you can copy the huge .MPQ file to the HDD in the game folder to stop it from wanting the CD.
With some games though, I've replaced my store bought CD/DVD version with the GOG version instead to avoid having to deal with a lot of that nonsense.
One problem with cracks though is that a shit tonne of them are infected with malware and may be heavily encrypted to hide it from antivirus/antimalware software. The readme file for the cracks tell you to disable your malware scanner to avoid "false positives" when in reality almost all of these are loaded with actual malware, as are 99% of the key generator programs out there and they just con people into disabling their antivirus protection so they can infect people's computers. That's a PITA to deal with, so unless I can find a truly clean crack I don't bother. It has to pass a barrage of 3 or more security scans before I'll consider installing it though.
In general, cracks are as much of a pain in the ass as they can be convenient, but it's best to avoid them if possible.