If people are just powering up and not actually purchasing Steem would it show up as trading volume? Rewards are pretty low right now compared to several months ago, so maybe people are just holding on to their SBD. The conversion rate is highly advantageous right now though, so I don't know why you wouldn't power up. It's also a great time to buy when you can pick up over 1 STEEM for less than a US dollar!