When I eventually, one day, maybe, in the far future, in a galaxy far far away, code my roguelike, it won't be pure Curses, and it should be simulated... I do know what you're saying, but I feel it only to a lesser degree, I guess.
Personally, I wanted to get to know a 2d library, and second, it can make the interface easier to use. I plan on having mouse-over menus and that sort of thing, just to ease the access to information. Overlaying stuff can really help, and usually, with the text output from every turn plus the char stats, you usually take up a lot of the screen. In a game where you might need a pretty constant and detailed update of what enemies are around you, using 'L' & arrows to find the enemy you want, then entering a new screen just for his info can really bring the game down.
Then again, it's not really the case for most roguelikes. There's also the eye-candy factor, but... we're playing roguelikes *g*.