Rock n Play / Bouncer

Emily
I keep reading raves about the Fisher Price Rock n Play, but I have a few questions:
1. Everyone seems to use it as an overnight sleeper - but I thought baby was supposed to be laid flat? I think I am interested in it more for sitting than for sleeping because of this...
2. If it is called "'n play", does this mean it can also be used as a bouncer seat?
3. I am mostly intrigued by the fact that it folds up completely. Are there other bouncer seats you recommend that fold up for travel and space saving?