Guide wear is a definite problem if you're trying to cast distance with a spinning reel on a fly rod.
Less so if you're using the reel primarily for line storage and doing something akin to pole fishing.
In the 50s they made Colorado reels for free-lining bait with a fly rod, essential the same thing as the type of drift fishing traditionally done with a centrepin reel ("steelheading").

Backing up to the pole fishing idea. I suspect even Theodore Gordon bait-fished with his fly rod.
In the "golden age" people didn't collect tackle like we do today. They were lucky to have one rod and reel, and used it for all their fishing. With braided lines, you waxed them only if you were going dry-fly fishing.

I remember fishing with my uncle. He had a fly rod with an auto reel and doubtful that he ever used it as a fly rod - he used it as a long reach pole for crappie fishing.