Document stores often are reliable and more fault tolerant. But yes they trade ACID.
There are some applications that require high throughput (usually write) but can be fine with read consistency.
Couple of examples
- consumer facing comment systems where other users are OK to miss your comment by 30 seconds
- timeseries logging where you are usually reading infrequently but writing very much in a denormalized format so joins aren't as critical
For general CRUD, ACID is important though.