If you buy a defective game on PSN and then get a refund, your entire PSN account is nuked. If you buy a game on Steam and the devs push malware in an update and you get a refund, your entire Steam account is nuked. An example of a defective game you can currently buy on PSN is Kingdom: Two Crowns. An example of a game whose developer pushed malware in an update automatically downloaded by Steam is Street Fighter V.
In the case of PSN, official policy is that defective games are refundable. They just make it impossible to reach anyone about this during the refund window. In the case of Steam, official policy is that devs are free to push malware to your device.