The answer is yes. Is an essential tool that gives you the right materials to create a product(s) with the desired execution. Most industries provide sample kits for those customers who are in the hunt of knowledge of the products, comprehension of how the materials affects the merchandise, what are the existing types of textures and colors available and so on.
The problem is that sometimes we rush to buy things, instead of studying the services and compare them with the leading companies for a comprehension of the process and better execution of our works. I have made lots of merchandise without a prior sample kits, and on some of those purchases I made, I wish I had a sample kit first. We all must be aware that the quality and the execution of our artworks might change when printed on merchandise, due to what materials, services and process the company runs on. We can even run the risk of having an undesirable product.
If you are unsure of what are you dealing with, then I suggest you to have an easy access on sample kits. It can benefit you in many ways, but it depends on what you are trying to achieve and where you are acquiring it from. For example printing industries like Blurb can sell you a swatch kit of paper stock, while Moo can send you, for free, a sample of stationery and on Ink it Labs you can either buy a sample pack of acrylic charms or a clear acrylic palette for better precision. Best of luck!