Typing on the keyboard is not what takes up most of the time in programming; thinking is. With static types you are forced to put more time into thinking about how to make the program compile whereas in a dynamic scripting language you only care about the result output. Your script may be ill-typed but if it gives the correct output for that situation then it doesn't really matter.
Static types save time later by giving you the opportunity to do a lot of refactoring with high assurance of correctness. Unit tests bring back some of this ability to dynamic languages but they require extra time to write and maintain the tests.
I just can't think of many situations when a dynamically/weakly typed program produces a meaningful result in that case. In my experience the errors are the same in both the (strong/static) case and the (weak/dynamic) case, with the only difference being whether the issue shows up at compile time or runtime. Dealing with N runtime issues is slower than fixing N compiler errors when you discover runtumr problems one at a time, but compiiler errors you get in batches of up to N.
Yes if everything is untyped then types are less useful. And for interactive scripring, compilation feels a bit strange too.
(Of course, I think text-only Unix tools as a way of interacting with a computer is a fundamentally broken idea).
Powershell is an interesting idea, though maybe not the best implementation of that idea.
"Yes if everything is untyped then types are less useful."
Everything sharing a common representation does not make types less useful. I would rather my program crash then confuse Bid and Ask prices.
"And for interactive scripring, compilation feels a bit strange too."
I wonder if you've used a REPL for a typed language. I agree that peeling out a compilation step would be odd, but adding types doesn't actually have to change the interaction that much.
Static types save time later by giving you the opportunity to do a lot of refactoring with high assurance of correctness. Unit tests bring back some of this ability to dynamic languages but they require extra time to write and maintain the tests.