Thanks, regarding bandwidth, the more steem power you have, the more bandwidth you have for posting on the blockchain. For example, a brand new member might not be able to make two small posts right back to back, while someone with a lot of steem power can make huge posts one after the other. If some app is using a smart media token, all of those transactions are also recorded on the steem blockchain using the bandwidth of the account that created the smart media token. So as that smart media token becomes more popular, that account will be required to hold more steem power, otherwise it will eventually reach its bandwidth limits. As for who they would buy steem power from, I guess the answer is... anyone! Most likely an exchange though. Or they could just make weekly posts about their token and power up those rewards, etc...

As far as I know, holding smart media tokens will never give someone influence over the distribution of steem power and SBD rewards, only the other way around.

Best,
Trogdor