If you look at the ends of any lumber for sale retail, and most of the commercial quantities too, the ends will have been painted and you are correct about the reason. It is to slow the drying so that it dries more evenly. Lee Valley used to sell an end treatment made from Poly Ethylene Glycol, PEG, that looked like parafin. One of my uncles says regular antifreeze will work too. Thick paint will work.
Wood is like a bundle of tubes that run lengthways up the tree, the reason long grain is much stronger than cross grain. The moisture in the wood doesn't travel cross grain easily but it travels very easily lengthways so the idea is to plug off the ends of the tubes to allow the moisture to dry more slowly. Rapid drying is pretty much guaranteed to cause cupping, warping, twist, and splitting.
I'm not 100% sure how turning works, maybe Bernie or one of the other turners will comment. I think it has to do with relieving stress before it can dry. I do recall one of the turners, maybe Bernie, saying once that he was partway through a bowl and he got company over and didn't finish it and when he got back it had split.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.