>Rubbish. Stuff like e.g. boats in the multi-tonne weight class are secured by tying knots every day. Spearfishers. Mountain climbers. I could go on.

Oil rigs are towed to location using steel cables. Steel wire rope is substantially stronger for its weight and for it size but generally harder to work with than plastic things of similar capacity. Both materials can hang pictures just fine. It's not exactly a dynamic load. People will argue over anything.