Having used static in the past, I can say that the only easy thing about it is so people coming from static languages don't have to learn the fluidity of JS. When I first started really using JS I heavily disliked it because all the restrictions that were once there were gone.

But after a week or so of solid JS coding I began to realize how useless it is to be as rigid as Java or the others. Let's say you have some data used by a few different functions that was passed in from some kind of input. And then that data is split into their own variables. Let's say that then you needed the data in those variables to exist in several different forms depending on certain conditions. In a static language, you'd have to set up a variable for each of those types. Not a huge deal, until you forget where what goes where and accidentally pass the wrong variable.

instead of having to remember three-four different variables for the same type of data, you could just remember one. And then mutate the data as needed to store again in the same variable as whatever data type you need. I mean like, imagine having a bank account per category. One for bills, one for play, one for buying fancy new toys. one for gas, one for food, one for work, one for vacation, one for...well, you get the idea. (Instead, you could could just have three. savings, bills, personal).