Steemit wallet limitations for traders of Steem!

I bought some steem on Bittrex Exchange and then tried to send it to my account on Steemit but found this not to be possible. However, it is possible to send Steem from my account to an Exchange using a memo etc, obviously only useful in a few years for powering down and cashing out I suppose.

I have since realised there is little point in holding Steem at all long term as the opportunity cost in regards to Steem Power is too great to make it a logical choice.

However, I was one of those unfortunate enough to be holding btc on mtGox when it collapsed and so am somewhat weary of holding crypto on an exchange for any length of time and would have seen Steemit as my best choice of a secure wallet for Steem short term. However, this is not possible.

It also prevents arbitrage and securing the best price for Steem if wishing to Power Up.

Any thoughts