Without shilling any particular game or project out there I could see a use case for this.
For seasoned gamers: Imagine you have the steam marketplace in your pocket and attached to you private keys. If the game publisher / creators ban your account, you still own everything that you bought. You can choose to make a new account and move everything you bought to that new account or you can choose to sell everything you bought.
For people that have never used steam or never played games: Digital collectibles. Digital sports cards. Digital jewels. Digital Hunting rifles. If someone tells you that you can no longer use those digital items you can sell what you bought before, either at a higher price or a lower price. It's all up to you.