Why not to use Riak?

Riak is great database that supports sharding, high-availability and works great in case of network partitions. Moreover, it supports CRDTs. The problem here, is provides no "lite" implementations. It means that you can not have Riak lite Db in the browser that is available for updates and queries, even if there is no connection to the server. And for us, optimistic UI and oflline-work is very important.