Here is why:

* No _changes feed. (TAPs won't do here sorry). I mean that is uber killer feature of CouchDB. Otherwise, just pick any other key value store.

* HTTP interface to DB : you can use CouchDB to store both your data and your code. That is very cool.

* Futon : that is the web based db and document browser and viewer. That is killer. Being able to see what is in your database and debug before that data is used by some other part of the system is invaluable.

The only thing Couchbase has in common with CouchDB is the name, and some of the same people are involved. If you like CouchDB, there's no particular reason you'd like Couchbase (and visa versa).

Because Couchbase has very different features and an almost completely different interface. For example, there is no changes stream, etc.

The name lies a bit.

I worked on both databases, they have entirely different advantages / disadvantages and use cases, none of the OP really apply to couchbase.

Big difference for me is that Couchbase doesn't have an HTTP interface. That is one of my absolute favorite features of CouchDB (along with master-master replication and the changes stream).