I don't know the exact reason why they decided to convert all cryptocurrencies to USD or EUR on their new sports betting platform, but it looks like Betfury set the minimum bet of 0,1 USD/EUR for sports events. Maybe they did it because of some legal restriction.
I like this conversion factor, for me it is much easier to place bets in USD and minimum bet is indeed 0.1$, which is low enough.
I don't really know why anyone would like this system - it doesn't make much sense because it forces you to also bet on the exchange rate with any bet you make. For example, lets say that BTC was at $30000 and you placed a $30000 (1 BTC) bet at 2x odds. Say this bet won a week later, but BTC shot up to $60000. Your payout would be $60000 at the new exchange rate (I confirmed this with live support), so you would get 1 BTC in return, meaning you don't get any real profit. Obviously it can go the other way around (if BTC dropped to $15000, you'd get a 4 BTC payout) and maybe it'll balance out on average but I still don't like it. The Stake model (show balance in USD, but actually place bets in BTC values) or the PlayBetr model (deposit crypto, converts to USD when you deposit, converts back to crypto at the current exchange rate when you withdraw) all make much more sense if your site insists on USD balances.
For bets at higher odds, it likely doesn't make too much of a difference. However, for sports bets on low odds (ex 1.03x) you end up betting way more on the exchange rate than on the actual event.