I happen to think a propeller on a fly, is still a fly. I like propellers on flies. I believe Tom Nixon used to hear a lot of stuff similar to what has been said here. Funny his book is a collector's item now. I admire his work a lot. Remember a long time ago people used flies that were much closer to a lure than a fly. Ray Bergman would use such lures/flies. When things got tough he pulled out the baitcaster, or he used live bait. I love to catch a fish, so I will use whatever method I think will give me a better chance of landing a fish. Most of the time I prefer to fly fish. But sometimes I just love using my spinning gear, or baitcaster. Once in a blue moon I actually buy minnows and use them. I'm with Ray, whatever works is what I will try to use. Some days flies tear 'em up, some days conventional gear is better. Usually fly fishing to me is better...so have fun with a propeller, and no guilt.