that's exactly how I design the parts of my app that need a transactional nature. Map/reduce views make it a breeze to query for a consistent aggregate view of the world.

This is not something new it's a well established technique from the relational world called "event sourcing"

http://www.martinfowler.com/eaaDev/EventSourcing.html

when everything is a write you don't have to worry about conflicts or locks, so that's nice, plus couch is really good at scaling write thoughput with small documents.