Just like a few users pointed out in the past. Its called SAFEDice because your BTC is Safe since its frozen. Since its frozen, you can't spend it. LOL! I know its a bad joke.
Yes it is safe to put your btc there, not just because of its frozen but it just take longer time just to withdraw thoae amount. You should not mislead people on the joke like that. They have not been actived on thread or have low support but you should know that they are always process your withdrawal, they just need some time because it is like one man play to be honest