Permadeath is a game mechanic some people like, some not. It can be both frustrating and extremely rewarding. When you finally beat a game that has permadeath, it usually feels like a real achivement. That said, permadeath simply doesn't work in a game such as Bioshock, for instance.
It's meant for randomly generated games such as FTL, Rogue, DoomRL etc. It's a specific genre and they are created and balanced around the fact that you have permadeath. You can, very often, rather easily get around the permadeath mechanic and cheat it. But this should really only be made if you are testing things. Because when you start cheating the game the sense of achivement, and thus the point of the game, is lost. When I started cheating in FTL was when I stopped playing. (Granted, I've finished it several times on normal, but I couldn't be arsed to unlock all the ships.)
I dunno, to me it's a game mechanic like any other. It has a point and appeals to a certain type of player. Just like regenerating health. Some like it, some don't.