I agree w/ the posts/thoughts above. The benefits I've noticed are that my endurance has improved, the increase of strength certainly helps when going against big guys, and mentally it gives you some support knowing that you've been fatigued but can still get the job done.
In particular, pull-ups,DLs and kettlebell work has improved my jits grips. Also I had tore some intercostal muscles earlier this year (very painful and slow to heal) but doing CrossFit and some power wheel exercises has strengthened that area up a good deal, though I've gotten pretty good at staying out of cross sides since then :wink: .
I think the oly lifts are great for BJJ too, the hip explosiveness can be really good for guard passes (hip in) and in general can help improve keeping your hips heavy (maintainig side control).
Sometimes it is tough to get up for a CF WOD, knowing that it may hinder your jits performance that day, but that is just one day, in the long run it pays big time dividends.