I ask for monetary reasons....there appear to be far more 30's in the world of stock footage than 24fps. I have no other reason.
Having said that, although I know how to do it, I don't want to degrade the content, which is why I ask...will it degrade?
If you are selling your footage then I think it doesn't matter and you are best off selling the footage in its native codec. I purchase stock footage from different places and I've never looked at what the frame rate is. Just my opinion.