Even if they are easy to pick it does not really matter… They have a counter and you can’t just turn that one back again. At least not without breaking a seal or some real effort. Back in the day when these were invented locm manipulation was not really in issue and no one thought about it. The locks were never improved and there was no need to because of the counter.
I have one of these padlocks and I also do have an original key, due to the fact that these are still in use and that I respect the American Law even though I am from Germany, I will not make pictures public nor do a video on it.
I may do a video on it one day but without showing the key in full detail.