The third party sites, which use Steam, don't need a card. You gamble with skins, so the kid can ask the parent for skins, and then gamble with those without the parent knowing. Also, the Steam wallet can be used to purchase stuff too.

In early complained about anti-competitive practices too earlier. That's what this one particular thing was about though, and it's far from just ads. They use Steam services to host gambling, and Valve let's them use their space to advertise. It's far worse than you're implying. I don't know if you're purposefully being obtuse or not.

Edit: I'm done with this. You refuse to change your mind, defending them no matter what (just because others are worse). This is made worse because you aren't even involved and don't know what you're talking about. You aren't even aware of the gambling controversy, which has been around for more than a decade. You aren't engaging in good faith. You're just arguing, and others have to inform you on every aspect, because you literally aren't even aware of the basics. Why are you even engaging? You haven't cared enough to engage and be informed, so stop wasting everyone's time.