I think you know the answer to this one. Yes, Paysafecard is safe to use at online casinos. In fact, it's the safest payment method a player can use because it does not involve sharing any of your banking details.
In case you are not fully sold yet, it’s regulated by the Central Bank of Ireland. It also uses two-factor authentication when you first purchase your voucher in case anyone is trying to use your details, and it can’t be hacked. It's as safe as houses, as they say.
This is why I personally like to use casinos that accept Paysafecard. If I ever doubt security, I can always rely on that method to stay gaming safely.