Official statement from Valve.
We shared with the NYAG that these types of boxes in our games are widely used, not just in video games but in the tangible world as well, where generations have grown up opening baseball card packs and blind boxes and bags, and then trading and selling the items they receive.
You’re right! We should stop that too!
Attempting to rebrand the terminology to “mystery boxes” like that’s gonna make it better ultimately comes across as so much shadier.