Sorry – have to disagree that BMXers don't want or need that much grip – if anything they need more as the grip is key in controlling the bike. The difference is MTB have wet conditions to consider where as BMX don't but I don't see that that makes much difference as grip is still key.
I personally run DMR v8s on my BMX and my MTB. The type of shoe makes a big difference too although I'd got for some cheap vans or similar rather than 5-10s unless I'm doing full on DH as if you can learn stuff with less grip you'll do better in the long run.
BTW – The plastic pedals don't seem to last that long, I know a fair amount of people who have snapped them from landing hard, but depends how you roll with them really. Worth it if you are just messing around learning track stands, manuals etc.
Good luck – well worth learning skills to help your overall riding. I still mince about but love being able to mince much better than before.