It does exist, see qbitorrent and similar apps. Torrents already fill the usecase you’ve defined: decentralized sharing of arbitrary files. The main problems being the central exchange and the need for seeders.
The bigger the central exchange (torrent tracker) the more susceptible you are to both internal and external threats, but you need to be big because bigger means more seeders and more content.
It does exist, see qbitorrent and similar apps. Torrents already fill the usecase you’ve defined: decentralized sharing of arbitrary files. The main problems being the central exchange and the need for seeders.
The bigger the central exchange (torrent tracker) the more susceptible you are to both internal and external threats, but you need to be big because bigger means more seeders and more content.