looks like he's mostly just moving some money around between his STEEMIT, poloniex, and bittrex accounts. I don't know his holdings, but from this video, he basically says he's more comfortable holding a larger quantity of more "price stable" SBD (Steem Backed Dollars). Perhaps he chose, as did @dollarvigilante recently, to take some off his crypto holdings off the table after the big runup.
While there are others (ie. bitshares BitUSD and USDT), it's another huge STEEMIT advantage to have a free to exchange internal market with a built-in crypto "safe haven asset" pegged to the USD (being the current global fiat reserve currency) that people can feel a bit more comfortable holding, as opposed to playing hot potato with crypto coins, or keeping your funds in a USD or other FIAT-related centralized exchange.
Just one more note: SBD was, of course, not nearly as much of a "safe haven" at $2+ USD, since the obvious downside risk was potentially 50%+ as more SBDs were printed in order to "re-balance" the peg. As such, BitUSD would have been the better asset to hold at that time.
Link: Crypt0's VLOG: Steem Dollar = Best Hedge Option During Crypto Market Panic?