I have not read this whole thread but here is the basics I know about chain vs. Straps.
Recovery straps are specifically designed to stretch and recoil,(Different from a rated lifting strap) which makes for a smoother better pull and removes stress on the vehicles since it has "give".
I have never wheeled with a club that allows chain on their trail rides. I broken strap doesn't render any serious injury. I broken chain would cause lots of injury to person and vehicles.
Chains are definitely not allowed on the competition circuit. IOn top of it, most semi-pro type competitions only allow synthetic line winches. They are very safety focused.
Last note, a winch weight is a line weight. It can be a sand filled bag (kind of shaped like a sadlebag) or a giant plastic puck that is on line(like a donut).