But if I'm not wrong they got a very high withdrawal fee for some altcoins right?
That's the reason I brought and hold coins for a while and then sold it for a profit and convert those coins to bitcoins and withdrawn to my account. That's why I go there only to buy coins which are not available in other exchanges.
That is what so many people say.
I never used HitBTC but many of the people who have cite their bad customer services and high fees as a reason to find another exchange.