High insulin levels should supposedly increase the cells creatine intake capacity, which is beneficial for muscle growth. In fact, some athletes resort to consuming refined sugars such as glucose or maltodextrose after the workout. The consequent hyperglycemia will lead to rising insulin levels naturally.
You must also keep in mind that these supplement products are a huge business, and often their products are advertised to be what they clearly are not. You know the doctor smiling in the catalog, promising that this special mix of simple protein(which you could simply get by eating a steak) is going to get you ripped in a few weeks and with minimum effort? Yeah well, his day job is probably working at a call-center in eastern Europe.
Therefore, a protein supplement featuring Insulin Amplification could contain some refined sugars and Acetylcholine and Phorbol Ester (they amplify glucose induced insulin secretion). Read Here. Or alternatively, and more likely, they wrote it on there simply because it sounds good, knowing that people who've heard of insulin levels affecting creatine intake will probably buy the product.
Is it safe? I wouldn't suggest you chemically amplify your insulin secretion, but neither do I have conclusive proof that it will hurt you. I can however assume that: Tampering with any natural equilibrium in our body is bound to lead to problems. The sheer amplification of insulin will lead the body to secret less and less in the first place, to the point where it reaches normal levels again. If you suddenly stop taking the product you could experience diabetes like symptoms until you system re-adapts.
Also remember, these high concentration protein shakes are a lot of work for your liver. For a young adult with a healthy diet it shouldn't be a problem, but don't overdo it. After 8 weeks max. I normally take a long break (I use standard Whey Protein LINK).