I was making a joke about AWS Lambda. It doesn't necessarily start up a new VM for each request, though; it can launch a new VM but it will reuse an existing VM if the same CGI-bin (oops I mean Lambda function) has been executed recently.
You're joking, but working in finance I witnessed the misuse of AWS Batch + AWS ECS to do something similar. Not gonna dox the company, but it was a German fintech unicorn.
It wasn't exactly for serving the response of the request per se, but a single customer click would launch an AWS ECS container with the whole Ruby and Rails VM just to send a single email message, rather than using a standard job queue.
It is extremely slow and super expensive. Amusingly, the UI had to be hardened so that double clicks don't cause two VMs to launch.
The rationale was that they already had batch jobs running in ECS, so "why not use it for all async operations".
