That person created NFC tags that can be scanned to automatically start a game when the tag is scanned.
The tag is added to a physical small box, cartridge-sized
Regarding ownership of the games files, they made a point about it at some point in the video, saying that they now only buy games from GoG to be able to just store the .exe files, DRM-free.
Music is a good topic they, that channel only has 2 videos, the second one being about using a dedicated music player ( https://www.youtube.com/watch?v=3EKV0oNN1Ak )
That player is 50 bucks, looks like a cassette player, has 8 GB of internal storage and supports SD cards up to 256 GB.