Static type safety has interesting YAGNI characteristics. For the bits of the code that must work, and where defects and regressions due to type errors may be subtle and difficult to detect, it's indispensable.
But it can also be an impediment to iteration. Sometimes the code you're working on is still so experimental that you don't really know what the best structure and flow of data will be yet, and it's easier to just bodge it together with maps and heterogeneous lists for the first few iterations so you can let the code tell you how it wants to be structured. Having to start with static types subtly anchors you to your first idea. And the first is typically the worst.
Something I really like about Python for this sort of thing is that I have a lot more ability to delay this industrialization stuff to the last responsible moment, and be selective in where I spend my industrialization tokens. Here's a list of the languages where I've found selectively rewriting the important bits in Rust to work well: C, C++, Python. I know which of those I'd rather use for prototyping, scripting, and high level control.
Relevant Fred Brooks quote: "Plan to throw one away. You will, anyway."