I had a very interesting experience around Azure function app when I was working at Agilytic. I tried to build an intensive workload application exclusively with Azure function app. It is a new kind of service called FaaS for Function as a service. You give a function that would be eventually executed following an event. The trigger could be a HTTP request, a timer, a message, … You quickly realize the benefit you can get of writing Azure function app. At the end you also discover it might not be that interesting because of financial reasons. Let’s read more: 

https://info.agilytic.be/blog/tech-talk-workload-solutions-azure-function-app