Why wine _before_ butter in shrimp scampi?
Because you want to cook (reduce) the wine down (or any other liquid).

Also, adding butter, usually cold butter chunks in the pan at the end will help emulsify the sauce.

in the grand scheme of things it is not a big problem if you add wine after the butter, but the result will be different, the wine will taste more raw, the sauce will not be as smooth.

I personally would not throw it out if it is for me only.