I trailer my boat and the previous owner did as well. However, it has bottom paint on it from the original owner who kept it in the water. It's not in horrible condition so I don't see the need to strip it off and I also don't see the need to repaint it.
However, when I bought the boat the previous owner mentioned that he liked to oil the bottom paint so that it wouldn't look chalky. Does this make any sense?
I guess when the boat is in the water it doesn't really matter and we are just talking about aesthetics while on the trailer.
Any thoughts? Oiling the bottom paint doesn't sound right to me but I am obviously a novice.
As you stated, its mainly aesthetics, regular ablative bottom paint will knock a little efficiency and speed off the hull, and if you don't like that, there are two methods to resolve it, one involves coveralls, sand paper and a respirator, the other involves a PEN

But I never heard of oiling the hull either.