Why don't you use Yobit for this .You can directly get your winning transferred there or can deposit it into gambling account.Also you don't need to sync the wallet that saves a lot of time.You can alsp excahnge to BTC or other cryptocurrencies in just a matter of time.
Basically, yobit's an exchange website(service). You can't really trust an exchange site forever IMHO. However, you do realize that yobit always have a problem that their buttons(options) aren't clickabe most of the time. How if they want to transfer the coins urgently & the service has a problem?
Yeah maybe, whatever you said here might arise but i was just setting up an example.Maybe he can continue with other exchange sites . Or,maybe continue with an online etherum wallet(like Blockchain web wallet for Bitcoin) for his gambling contest.