This is the library that powers the "style transfer" feature in Facebook Messenger: http://caffe2.ai/docs/AI-Camera-demo-android.html I think Caffe2 is especially suited to machine learning that runs on mobile devices, so I wouldn't be surprised to see it become more popular as that mode of machine learning becomes more popular.
What makes Caffe2 especially suited to mobile devices?
We also did a lot of optimizations on the mobile side - like using NEON, mobile GPU and stuff for optimized speed.