STEEM deposits and withdrawals disabled at Poloniex?? What's the reason? I have an account at Poloniex too but I guess I'd better stick to Bittrex for now.
The reason why a lot of STEEM are stored at the exchanges is obvious - many (most?) people buy just to speculate. As they do (and many of us too) with other coins and tokens.
However, I believe an increasing number of people will gradually take these out when they realise they can actually use STEEM right here and now. Unlike most other cryptos, their projects are still "out there", "being developed". Some will not see the light of day. But Steemit and dtube are already up and running. Not perfect yet, but a few levels ahead of those other projects.
The fact that there's a real world use for STEEM - this is the main reason why I don't care too much about its daily price fluctuations.
Yes, STEEM is a usable currency, probably the only one that has a product that's live and that you can see at work. One other thing that's gonna make STEEM very valuable is that there is value in holding it as Steem power, as you can "mine" it by participating on Steemit. I see a future where a lot of Steem will be held in Steem power, and very little circulating. Making STEEM rise in value incredibly.
I know of no other crypto that has anywhere near this type of value; it seems to be the first.