Of course it's good to think about what you're passing, and why! Nobody disagrees with that. The issue is, can you think carefully enough, consistently enough

Of course it's good to think about what you're passing, and why! Nobody disagrees with that. The issue is, can you think carefully enough, consistently enough, so that you don't need static types? Can your coworkers - all of them? What about future you, and your future coworkers? What about that time that you're in a hurry, or going on vacation the next day, and you're not at the top of your game? If computers have taught us anything, it's that automatic processes are more reliable than manual ones. Personally, I just inherited a code base that is a decade old. I haven't measured, but I'm pretty sure that it's more than 100,000 lines. My current coworkers have two weeks longer on the code base than I do. Static types make this a lot easier. And, if your approach to static typing is "mush-mash that passes the compiler", no, static typing may not save you. But dynamic typing wouldn't, either, with that approach.