Sounds interesting. How do you store assets? Unless it's a tiny game (for which UE4 isn't a great fit either) you could be looking at having to download 100MB or more every time you launch the game.
Even if a user doesnt have cached assets (which i think is the main point against your supposition, that assets can be cached after first launch), ideally a modern game could still load very fast at very low fidelity & keep pulling down higher fidelity assets as the user plays.