If you buy smut game on Steam, your bank statement won't show the name of the game. It looks exactly like any other transaction you make on Steam.
> "Hunny what is this transaction on our account for BigBussomsCom?" .. "Oh must be some kind of fraud" "then let's call the bank and straighten it out"
This is a scenario that literally can't happen in the Steam case. It could happen with Pornhub but not with Steam.
And Steam has a very generous refund policy. If your playtime is less than 2hr you can ask for a refund with a few mouse clicks. No phone call or email needed. Actually in my experience if your playtime is just over 2hr for a bit they'll still refund you.
If you chargeback you can get your whole steam account suspended.