It is mentioned on steem-engine they would charge a 1% fee from withdrawals. It also states how much satoshi I would receive on the destination address.
However, there is a hidden BTC transaction fee on top of that 1%. It is not obvious this fee is there because there are services offering free BTC withdrawals. The most noticeable example is the faucets service, which usually profits somewhere else.
I.e. if I deposit and then withdraw to and from coinpot, I will not lose a single satoshi.
When trying to get help on their tech-support Discord chat, this is the answer 
First of all, even if BTC has it's own transaction fee, it's adjustable. Second, if an exchange fee is used, it could easily be displayed. Last but not least, none of that is mentioned anywhere!
If either were displayed I would not have chosen to withdraw in the first place... But I'm not getting refunded. Small traders, stay alert.
