I can definitely see the benefit of two beds, even though I've never done that myself. Both of us are probably detrimental to each other's sleep, and it doesn't help that she sleeps from ~10-5:30 whereas I sleep from ~1-7:15. So I'm always getting situated while she's already asleep, and she wakes up while I'm still sleeping. Thankfully there have never been any issues with us waking each other up, consciously, but I realize that it might not make for the soundest sleep.
And an aside from earlier, generally, sex just flips a switch for me; if I'm tired it completely wakes me up, but if I'm fully energized it leaves me wanting to sleep.