Fudge... I just wrote a program wrapper for Bittrex API. Well I'll stick with them for the moment and see if my trader bot makes any gains. 0.25% does not sound like a lot but 0.1% will mean a few more bucks saved every trade...
As I understood, with binance you have to have some holdings in BNB for you to have that discount and this 50% will turn less in coming years + have in mind that binance will slowly be buying those tokens to reduce the supply (because with BNB they have been founded through an ICO)
Some things to read:
https://support.binance.com/hc/en-us/articles/115000583311-What-deductible-fees-does-BNB-charge-
https://steemit.com/crypto/@therealwolf/bnb-and-binance-explained
https://www.reddit.com/r/binance/comments/7jkssk/using_bnb_to_minimize_trade_fees/
tldr: if you have to pay a fee for any transaction and have some BNBs on your account - you can select to pay with BNB's with 50% discount (for next 6 months, then 25%)