That's about the worst way you can spend $800-950 on a PC. You can build a pretty good computer for that price. Or buy a couple 27" monitors.
it's obviously for people who already have all that and just have extra cash to burn. besides, let's not forget:
your case is typically the last thing in your rig that will "expire". also, it is the first thing your friends and family will see. it also adds a unique, personal touch to your build, depending on how your mod/decorate it. I think far too many people forget that the case is so much more than just a wind-tunnel to keep your components cool. but how much attention/money you spend on the case is entirely up to the buyer lol