Commercial gelatin is a refined product derived by soaking mostly animal hides in an calcium hydroxide or acid solution to render it.
I prefer the slow simmered bones, tendons, and parts such as ears and feet that still have skin that make that collagen jelly magic happen right in my own kitchen... it has the added benefit of mineral... and delicious flavor.
There are at least 15 types of collagen, making up about 25% of all the protein in the body. It is present in bones, ligaments, tendons and skin, in cartilage, and in bone marrow.... I don't think the diversity that is found in bone broth will be found in a package of refined product made mainly from a single source (skin). "Most commercial gelatin products are made from animal skin and often contain MSG, but broth made from bones produces a much more nutritious gelatin that contains a wide range of minerals and amino acids."
I can't say if the refined product would be as effective or not... but I have serious doubts.