You should operate under the assumption that whoever you're doing business with is going to scam you if given the proper opportunity. What I would suggest if moving forward with this in mind and always using escrow, or securing your transactions to the fullest extent possible. There is never a fool-proof method to avoid being scammed and when you're purchasing off-market goods/services there's always the high-chance you're dealing with a shady individual.
The only tried and true method to use your bitcoin to purchase any steam games without getting scammed is :
Exchange your BTC for Fiat via a trusted exchange service and then purchasing the games directly from steam, while securing your steam account as fully as possible.
The only tried and true method to use your bitcoin to purchase any steam games without getting scammed is :
Exchange your BTC for Fiat via a trusted exchange service and then purchasing the games directly from steam, while securing your steam account as fully as possible.
This unfortunately defeats the purpose. If you need to exchange for fiat it's not worth the hassle, might as well just paid with your fiat in your bank account, steam games aren't that expensive to lose some Bitcoin over it (count in the exchange fees etc).
How safe is buying a steam gift card with Bitcoin then using that to buy it? I can't also trust random people selling me serial keys.
It's usually less than a dollar for buyer's protection and that's quite cheap to ensure that you don't get scammed, they're really cheap anyway.