> it takes the same amount of time
in my experience it doesn't
1. refactoring are in my experience still much faster (and reliable doable) with rust compared to e.g. Js/Python even in presence of a lot of tests. This is a bit less of an point with Java/TS/C# etc. through I had some very bad (and also some good) experiences with refactoring in TS. And to be clear I don't just mean pure refactoring but any larger changes affecting many places in code which might be needed to idk. impl. some feature.
2. especially with Js,Py and similar there are way to many edge cases you can have to test for all of them. Sure most times this mainly matters when writing libraries but on larger projects does apply too. Stupid stuff like you expecting a `list[int]` and someone (externally i.e. outside of your tests) passes a `dict[int, int]` and that happens to work as you current impl. is only linearly iterating it as if it's a `Iterable[int]` but then you change the impl to require a `Sequence[int]` as you access it by index in some corner case and now you customer has really strange subtle bugs. Can't be caught by your tests as the problem is the customer but still breaks the customer which is always bad and can't happen with rust. Sure also won't happen if everyone uses type annotations and mypy correctly and strictly. Through you can't rely on your customer using mypy, but you can rely on your customer running compiler checks (as it's the only way to build the code). Also while mypy is much much much better then pylance it is still prone to issues as both `cast` and `ignore[..]` are things you sometimes need but which easily can hide bugs if the code changes (cast doesn't pin the "from" type and ignore is scoped by place not by what is wrong)