Let me ask the question a different way. If one has a (high end) vintage frame already stripped, is there any harm to spending the $13 on Frame Saver? Can it mess up the paint, or cause issues down the road?

Further questions:
If said vintage frame is going to be repainted professionally, should the Frame Saver be applied before or after the paint?
And will Frame Saver do anything to mitigate against the possibility of a stuck seatpost or stem?