According to my son, it's about how you route the free end. There can for example be problems when you load in rain. Then temperature goes down, the strap freezes and you get problems when unloading. In this video
it is shown briefly, but that guy don't prefer it. Anyway, I think that video gives more useful hints. It also briefly shows one-piece ratchet straps, which I mostly use when I transport motorcycles, especially Vincents. Kinder to the paint. The hooks on the usual two-piece straps are often hard to attach to a bike. But you can make a loop by hooking the hooks together. Not practical on a Vincent though, where you strap the RFM.