STEEM is just a short-term, highly liquid part of the puzzle. I hope people realise it's not designed to be held. In the short term, we may see the exchange market value STEEM highly against the Dollar. But long term, once the 100% inflation kicks in, I expect STEEM to start devaluing.
Steem Power is the best long term investment - but of course not everyone will be OK with waiting 2 years for powering down. It only works if you are invested and believe in the long term success of Steemit. If that comes to pass, powering up now will pay off massively later - no crazy compound interest required.