I think much of the benefit of CQRS lies in the business value inherent in
the domain portion of the project, not necessarily the different storage
implementations.  Albeit, I usually have seperated read and write stores,
but CQRS doesn't require that.  The data store is largely an implementation
detail  I can distill the same data store into a write model and read model
at the same time, making the benefit to be driven by the behaviour of each
of those models rather than the data store underneath.