That analogy only really applies if you stick your serverless function behind an API gateway and invoke it through an HTTP request; honestly, AWS lambda behind

That analogy only really applies if you stick your serverless function behind an API gateway and invoke it through an HTTP request; honestly, AWS lambda behind an API gateway has always felt like a pretty poor way to build a microservice. Serverless functions seem to come into their own when they're connected to a reliable event triggering system - that looks to be the really interesting part of OpenWhisk, that it adds extensible triggers, much like the way AWS lambda can respond to events within the AWS ecosystem - but platform independent. In a high volume event-based world, small stateless processes become a very appealing idea again.