The materials metal and plastic have quite different qualities which can be used tor the individual strapping duties. In general  metal is more insensitively against heat and plastic has better strain values. All factors which work on the load must be considered by the decision for a material. Example overland transportation :

Braking – forward active forces
acceleration-reverse active forces
Cornering – sidelong active forces
Compress (piles of loads).
Static forces (e.g. downhill and mountain drive, fiber bale expansion).
Vibrations (oscillations during the transport by truck, road or ship).
Pushes (lift truck, train-shunting pushes).
Weather (moisture, air humidity, temperatures).
Extent decrease (by piles of loads, dehydration)