I also had a no-name digital camera that inexplicably supported JPEG2000.
Other than that, I’m don’t think I’ve seen it much in the wild.
It is also used for digital cinema distribution. It was chosen for that role specifically because it was not in widespread use.
To be fair, the same was true of the original JPEG when it was released. JPEG also has an optional arithmetic coder based on IBM's Q-coder, which was heavily patented at the time. To this day, no one implements that, even though it does improve the compression and even though IBM's patents have long expired.