Onehash does have this kind of feature but it's just an option for the bettors. If you want to register, it's okay but if you don't want to, you have an option to deposit anonymously and you will be given a certain bitcoin address to receive your winning. And after that, the deposit address will be given to you so that's how you bet without any registration. You are not enforcing your gamblers to use it but you are making their lives easier by providing an option.
Even if you make an account on onehash, your identity will not be disclosed. Making as account is always better because in case of any issue/ dispute you have at least an account to take up the matter with support.
The only way the identity can be disclosed is by doing the KYC. Making account will never have any impact.
Absolutely and it has more positives with no negatives only if there is a problem if the registration takes our ID to be verified.Normally many gambling sites doesn't ask for KYC until if there is an issue so playing with reputed sites and small amounts will make us to be anonymous.
Keep in mind that KYC needed at certain circumstances to verify the real owner if there is hack attack on anyone's account which has something more positive.