[aardvark179]

In this case git can do the same thing, but notice you can only do it because git provides a special command for getting that revision. Recasts are really general (a greatest common ancestor function is provided, but can be easily synthesised from more primitive building blocks) and can be used everywhere, so you can bisect over changes you made that touched files matching a pattern, or whatever. They aren't something I use every day, but they are really useful on occasions and allow for some pretty robust tooling to be written.