Images, music and 3D models reward system for games- how could it be done ?

Hi.

Firstly, what if a game could be handled almost entirely by a community, and instead of game related goods, such as items or achievements, actual assets are dumped in a folder. Let’s say a man sets up a server, for your PvP game. He also has the ability to create and shape maps (modding enabled) . He could giveaway assets for other people to use on their servers, by completting tasks in his game world. Other players could in turn create their world with the assets, and offer new ones as rewards.

Is this system better to encourage people to play your game, especially creative ones, than using Steam achievements ?

Also, how to create such a system in UE4. How to make files inaccessible until they’re unlocked, in a compiled runtime build ?