In that part, I was speculating. As far as I can tell it is indistinguishable from converting, and by converting you are destroying Hive and creating dollars. Just as a chemist can destroy water and end up with hydrogen and oxygen gases. There is no trading involved. You can trade though and it is advisable to trade on the internal market rather than just get only $0.10/Hive. You'll be able to get around $0.22-0.29/Hive on the Internal market.
You can take your dollars and put them in savings. Get 7%/year. That's not very impressive though. I get better powering up POB and curating...