I believe that your idea may well have potential. Exchange trading options on cripto-market have not yet been developed, you will be the first this will give a good advantage. You can choose any commissions and tariffs for maintenance.
But it seems to me that the commission of 0.5% is too big.
For a exchange trading options for crypto currency is a small amount of commission.
Do not forget that your purchases will also be insured.
There are no competitors at this exchange at the moment on the crypto market.