Google docs, really any online collaborative editor uses them. If you have a distributed system with multiple asynchronous data feeds into the same sink, this is one way of automatically resolving conflicts. A complicated way that most applications probably don’t really need, and that does not guarantee consistency. But they are neat.
I'm pretty sure Google Docs use Operational transformation (OT). Google Docs pre-dates the paper that defined CRDTs. It's certainly possible they've updated their algorithms since then though.
