I can't remember exactly what the use case was but we used at my old work (Start up providing a Web CDN/WAF type service, think the kind of stuff CloudFlare does nowadays) in ~2013 for some sort of batch processing analytics/billing type job, using MRJob and AWS Elastic Map Reduce over a seriously large data set.
The performance of PyPy over CPython saved us loads and loads time and thus $$$s, from what I can recall.
The performance of PyPy over CPython saved us loads and loads time and thus $$$s, from what I can recall.