We used it a lot some years ago when we built a chatbot for FB Messenger. It was a great surprise. FB analytics was very hidden, but once you got there their product was quite good. Simple to use and gave us 95% of everything we needed to know.

The problem was that you obviously needed to use it with Facebook. As we started building a FB chatbot, that was not an issue, but for any other product it didn't make sense.

We considered:

- Mixpanel was way too expensive for us.

- Google analytics is definitely not a product analytics tool.

- Game Analytics was a good tool, but too much focused on games.

Analytics tools can be very expensive and there weren't many good free alternatives that we were aware of.