I currently misuse the hotcues to mark 16 and 8 bars out from the end of some songs so I can see these points approaching, and start my fade appropriately. There's something about having a fade beatmixed properly, but being off by two bars (Or worse, an odd number) that annoys me personally. The only thing about doing this that bothers me is the fear that since I'm setting these up as hotcues, I'll accidentally slip, hit a button, and fly to the end of a song. Personally, I'd like to see some non-cue cues. I'd love to drop some kind of markings in a song that are purely informational. Of course, the next logical extension of this is to allow the passing of these markers to auto-start the alternate deck. It's totally cheating, of course, but very effective.
I have a couple songs that I usually like to play back to back. The first ends cold, and the second starts "cold". There is no time to beatmix in the headphones for this transition, you just have to set the cross fader midway, and try to get the timing just right. If you miss it, even by a little, it totally ruins the effect. I'd love to spend a couple minutes offline tweaking these markers, and then not worry about it at the club. As I said, it's totally cheating, but it would allow less technically skilled DJs (myself included) to move some of the effort to the planning stage instead of execution.
These markers could also be useful for the auto-dj function.