Restspace does Lambda better
One of the ways to explain Restspace and its potential is to compare it to existing technology. The closest example is that of serverless functions.
A serverless function is simply a piece of code which a cloud service will run whenever something happens. You just give your code to the cloud service and it runs it without you having to worry about what it runs it on, or how it will scale. Commonly the function will run in response to a web request on a url, the function processes the request and returns a response.
This is generally perceived as having two major advantages: you don't have to worry about how to scale, and you don't have to worry about setting up and configuring servers. There's also a third thing you're getting which is seldom discussed as such, which is the ability to easily attach an http message processor to a url. Before serverless functions, you would have to write a webservice and set up somewhere to deploy it to in order to achieve this. With serverless you build a request handler and upload it. Maybe half the effort, and then you have no future scaling worries.