Binance is taking 13% of Steem volume now. That's a couple million $.

my guess why it may be popular on Binance.

If you withdraw ETH from Binance, you pay 0.01 ETH. That's 10$. Not that low, right?
Especially if you are small investor/trader.
If you withdraw LTC (more lightweight coin) you pay 0.02 LTC.
That's approx 3$. Less then ETH, but still a lot for a small transaction

what if you withdraw Steem?

If you withdraw Steem, you pay 0.02 Steem. For 3$ steem its 0.06$. 6 cents! And also Steem transactions are costless, which means that you can send it back and forth without fees.

so, for someone who did like 10$ in a day it would be a good idea to convert that money into Steem and then sell it somewhere or through Blocktrades.

thanks for attention