So I agree that for most jobs taking already more than 300ms, a 50ms per job will not be perceivable anymore. What matters is the DX and even though I'm very proud of our performance, a lot of our work is focused on providing a consistently great developer experience in all aspects (vscode extension, instant deployment, etc, etc).
However, there is one big benefit to being performant which is that you can use the same stack for performance sensitive jobs such as event-streaming use cases. That remove the duplication of infrastructure. The other benefit is that it improve the developer experience overall with fast previews.