At a guess:

• People with steam accounts and VPNs in countries that steam doesn’t operate in. Steam will block your “foreign” credit card as a fraud risk, but eBay dgaf cos it’s the sellers problem if they get ripped off
• This is probably a pretty convenient way to send small amounts of money to people in a way that looks pretty legit. Arrange to buy some drugs off someone over telegram, they get you to buy a “steam card” from them, they send an envelope with a blank bit of cardboard and the drugs

So realistically, what would happen if there was a collision like this?

It’s a pretty significant hit, but not enough to meaningfully change the moon’s orbit, so no long term impacts from that. Maybe a pretty meteor shower from the material ejected? Probably not enough material to cause a significant amount of surface heating.