Have you done much with a framework like Serverless? The simplicity comes in because you can start writing business logic functions immediately. Plain Node typically uses a library like Express or Hapi. While not complicated, it is one more thing that is boiler plate and doesn't provide any business value.
If the app needs a queue or messaging, sticking to plain node does not really change the need.
Express and Hapi seem simpler than the Serverless framework you're replacing it with. You have to specify that one more thing[0] anyway, don't you? I honestly don't see how this is simpler.
If the app needs a queue or messaging, sticking to plain node does not really change the need.