It will be really great if user have ability to choose few options of transactions fees(for BTC,ETH ) on withdrawal page , for example
(for BTC)
(1) Transaction fees: 0.0001 BTC ( kan waiting couple of days to get confirmed)
(2) Transaction fees: 0.0005 BTC ( up to .... timer  to get confirmed )
(3) Transaction fees: 0.001 BTC ( up to .... timer  to get confirmed )
... etc