That, and how much extra weight would you be carrying with the heavier binders and bigger chains? Granted, you're a little more weight-conscience than a guy with a gooseneck, but still. You'd need at least 8 chains if you had the 3/8 instead of the 5/16 anyhow.
I also like the idea of getting 20 footers and cutting them down to what's needed, or 14 footers and a spare specifically to be cut down. Then you throw a set of hooks on the remainder and have some shorter spare chains. Then if you need 16 or 18 feet of chain, you can easily go up to about 19 1/2 feet instead of having a pair of 14 footers at 28 feet. And sometimes hauling equipment, you can get creative with a couple short chains and still have the longer ones for something else.
I'd also say it's hard to have too many chains or binders. I've never found myself complaining that I had a spare chain in case I needed it when I had something loaded up.