It is safe, yes. But being a highroller you are only welcome if you play casino. If you play sports and win, you get shown the door real fast, as stated above. Where is the fun in that?

And, who wants to play to lose, nobody. 

If I would play and win million, I would be afraid if I get paid for sure. Wouldn't know how to pass KYC part 4, proof of funds. First of all because I didn't keep old wallets that I used in the past, and second because most of the money I deposited came from private deals/work where I got paid in crypto, or for example from signature campaign here, and so on. This gets rejected real quick, as we have seen in a scam accusation in the past.