I got the email from "Roobet"
The email give me information about instant deposit bitcoin, did this feature will be no confirmation for the transaction of bitcoin.
You can get a problem if someone using "double spend" the transaction.
How, you selected the user for instant transaction, did the player need to wagger/deposit a minimum amount?
Yap that's what is meant by instant deposit, means that you can play with your deposit without waiting any confirmations.
Indeed it is a bit risky of double spending, but I do think any sites offering instant deposit are aware about it and knows how to deal with it.
If there is no requirement mentioned on the email, I guess this instant deposit applies to all players without any requirements.