Yeah the site is legit but as he mentioned the website didn't pay few people because they had earned profit. So if you bet 1 btc which is 1300$ approx and if barcelona wins you will get 1560$ which should be withdrawn and should not be used again to bet.
Regardless the nature of Bitcoin payments as a regulated operator we are obliged to ID verification, KYC and AML (anti-money laundering) procedures by the regulator at certain withdrawal levels.
We have stated this clearly in our Terms & Conditions page available here
https://sportsbet.io/about/general-terms-and-conditions3.3.3. Sportsbet reserve the right to carry out additional KYC verification procedures for any withdrawals exceeding the equivalent of 10 Bitcoins or 2300 which ever is lower, and further reserves the right to carry out such verification procedures in case of smaller withdrawals, as demanded by our gaming license. Account Holders who wish to recover funds held in a closed, locked or excluded account, are advised to contact Customer Support.