We are using Apache JMeter for profiling and stress testing the application. It is a part of our delivery architecture to stress test the application. It is a part of the build chain. It is not just something that we use internally to verify what we are going to use or going to do.
In terms of a specific use case, we are using Apache JMeter to simulate user engagement. Our software is about customer engagement, and we use JMeter to simulate the customers and engage them on our platform as aggressively as we can.