Thanks, I was thinking the same thing but wasn't quite sure.Seriously...there's little worry here!
Technically, typical Interior resins are a little harder. Exterior binder-resins are usually slightly more "flexible".
It'll probably wear just fine. Slight odds of it cracking earlier, depending on the wood' movement.
Wolfgang, very interesting.First thing is to turn in your Painters Card.... just kidding. 6 years ago I had a guy do the same thing to his porch columns, we went over it with oil-based CoverStain primer and topcoated it with exterior. Other than the regular exterior grime they've held up through the Nebraska weather extremes. Might want to give it a shot.