A friend of mine recently went out on a first date, and when I called her the next day to see how it went, she said she had just finished having brunch with him. Naturally, I assumed she had spent the night, but she said that they just had a good time and decided to make plans to have brunch the next day. Then she said, "Besides, I wasn't gonna sleep with him, and PG sleepovers aren't really worth it."
My brother and I concurred. They're not worth it. You end up making out and dry humping like a 13-year-old, for way longer than you want, which hurts when you're both wearing jeans. You spend the whole night in a semi-conscious state, sexually frustrated and holding in farts. Then, when you finally give up on actual, qualitative sleep, about three hours before you would normally be getting up, you have to muster up the strength to limp your swollen balls to the bathroom to jerk off so that you're physically capable of walking home/to your car.
That's not to disparage a good "make-out sesh'," especially on a first or second date, but in that event, there's no need for anyone to spend the night and sacrifice perfectly good sleep.
(Special thanks to Fixy!)