Serverless architecture

Recently I've heard about idea called "serverless architecture". This is the next architecture proposal for web applications after very popular in recent years microservices. To be short, in this approach developers don't have to care much about server-side infrastructure. Great description can be found at martinfowler.com. Serverless concepts can be found in big providers' platforms like AWS or Azure. As I see on Azure platform there is 1M free function invocations per month what allows to create & start small applications for free. Development can be rapid due to provided integrations (in Azure - Logic Apps) with popular services (Salesforce, Office 365, Twitter, Dropbox, Google services).