A Python script can start and finish in less than 10 ms on my machine.

Even with installing dependencies?

Because that's what dotnet run does

Does dotnet install the script's dependencies all over again every time you run it? The quoted part was about the 0.5 second startup overhead, which I figured did not include installing the dependencies.

Anyway, lots of Python scripting can be done with the standard library, without installing any dependencies. I rarely use third-party dependencies in my Python scripts.

1. I don't think so, but it may check it if is needed? I don't know.

2. Same can be said about C# which has really strong and well designed (APIs) standard lib.