1. Mr evil uses stolen credit cards to buy game licenses.
2. Mr Evil sells those game licenses on this marketplace to Alice.
3. Alice has paid her own money for this game, starts playing it, maybe buys a few in-game items.
4. The original card owner disputes the charges.
5. Now, if the game manufacturer disables the game remotely, they will take a PR hit from Alices vocal complaints on twitter. Yet if they don't disable the game remotely, they continue to loose revenue.
Typically the keys come from legitimate promotions such as the Humble Bundle, but purchased (as you said) with stolen card details.
Surprise surprise, the bundle sells 150 units, you make $5, and suddenly you have 50 copies of your game being activated everyday for the next year.
Just a note to indie devs out there: unless it’s a colossal site like Humble Bundle, all game bundles are scams. Ask them if they can return unused keys to you after the bundle finishes and they’ll suddenly stop replying. Legitimate sites have no problem doing this if sales really ended after the bundle did.
If the game is on sale in the poorer country, all the better for the reseller.
With the Internet, I imagine this is all very easily done.
Pretending to be an "influencer" so you get free press keys
Buying keys in a region with low regional pricing then reselling them in a higher region
Buying a bunch of keys during a sale, then reselling them a couple of months after the game is no longer on sale
Steam has lower prices in some countries. Factorio sells for the equivalent of $12 in India while it sells for $30 elsewhere. Most games are similarly discounted. That said, someone who buys it from Steam can't gift the game (or presumably extract a key) to someone in a different country. If you bought the game in India, only an Indian account can play it.
Notice that companies can do that with labor and buildings and tax evasion, and it's 'situation normal'... But when real humans try to, its bad and illegal and horrible.
Hmm.