Originally Posted by Calchas

Have I been doing it wrong all this time?

With palm forwards I can use my (slightly) more powerful bicep to pull my bag along sharply if there is an abrupt change in the friction encountered by the luggage wheels. I prefer to have the bag pulled alongside me rather than trailing behind, so it cannot run into the bag of my legs should I need to stop suddenly, and this is easier with palm forwards.

I don't think the rotation extends too far up into the shoulder, but not suffering from any debilitating chronic skeletal-musculature weakness I never really thought about it before.