Interesting idea...been thinking of doing something similar on my own.
And I agree that scopes do not allow for "accuracy" in paintball, they do allow an experienced user the ability to snap up and potentially drop first rounds on or near target more accurately and more rapidly. But again this is only for the experienced user who knows his gun and its behavior. While paint varies tremendously it does not take long to learn how that functions in your marker.
And I am in no way saying that scopes work as they were intended to do (100 yard shots dead on the cross hairs) but just as a rifle can work as a club a scope can have a secondary or several alternative uses. Providing optical zoom for a camera to capture the hit...similar to Enterprises zoomcam, this is an alternative that uses a phone. Or just as a simple replacement for iron site sort of activity where you do not have get your mask down the barrel and around the air tank and such....it could work.
See I have a Droid Razr that has a nice HD Video camera in it that the glass is cracked. I was thinking of getting new glass and get a waterproof box for it and do something similar with it. without the phone being active and disabling the wireless and other crap while playing the battery life should get me a few hours of some decent footage.