I actually think the opposite. Serverless architectures are the future for most of the app servers that need a language agnostic API. Maybe I didn't get it right but to me BaaS is just a PaaS with a common API interface(i.e. authentication, input/output serialization, cache etc).
There's a pragmatic definition buried in the article... if you can't spin up your app in 20ms and run it for half a second effectively, it's PaaS, not serverless.
