"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.
(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.