The pattern I see, is every major program needs both a command line language, and an object oriented API.
You can test things so easily at the command line, so development is pretty easy.
The OO stuff is easier for larger programs with lots of settings and things being passed around.
Its the ability to run stuff on the command line that is so slick in lisp. I can test (car nil) to see if the Car function freaks out on a nil.
No way to do that in .net, you must set up a test program, then step through it.
One nice thing I figured out a few months ago, is the quickwatch window in VS.
You can type in any simple statement to see it evaluate, like someVar.GetType().ToString().
You can type in anything to see if it gives a value, helpful when investigating if you are doing what you think you are.