He has learned a lot from his MegaUpload and Mega.nz cloud solutions. Specifically Mega.nz gave him a chance to explore end-to-end encrypted solution and he obviously wants to take this to another level with MU2.
And when he says 'perfectly legal' masterpiece, I tend to think more than just a cloud storage for pirated content. A direct-selling market place for artists and content creators, perhaps?
And you just believe him, because he said it is perfectly legal masterpiece? maybe i missed something, but where is his proof? all i heard so far is that he is planing a centralized service to solve the transactions problem. he lies if he can profit from it, like he did before.
I am speculating right now but I imagine this Bitcache will be evolved version of Kim's current project Mega.co.nz uses encryption for client-side communication.
This way even if people would upload illegal, copyrighted materials it wouldn't be possible to blame the service for it.