It's ok.
You have to keep going when you're tired though to have it push yourself (to be a good conditioning session)... which may screw up yourself neurologically learning skills as you get sloppy. The good part is you're manipulating your bodyweight though so you're gaining great body awareness and an overall increase in neurological activity.
I'd still stick with bdancing as a form of technique training (like tricking) with strength/conditioning on the side though.