As the capsaicin in peppers is what is important, not the source of the capsaicin to reap the capsaicin health benefits for diabetes glucose control, it doesn't matter all that much what your source is to see the capsaicin diabetes link. Dried chile powder diabetes benefits will be the same as any other capsaicin source, as long as you have the same amount of 'hotness' as you vary the source.
If you want to save yourself money, however, you will want to avoid buying dried chile powder for diabetes control through capsaicin blood glucose lowering effects. The reason for this is simply that as soon as you grind a dried hot chili pepper to a powder to make it easy for you to digest it, it makes it just as much easier for the capsaicin to be lost with time. You will find that store bought dried chile powders have much less hotness (the capsaicin in the peppers has been lost) than fresh ground hot chili powders you make yourself from good quality dried hot chili peppers. The 'shelf life' of chili powders is low, if you will. Same goes for chili mixes for vegetarian chili or Texas chili mixes - all these pre-powdered hot chili powder sources are prone to lose their potency with time.
The best way to have the highest quality dried hot chile pepper is to prepare the ground hot peppers yourself by grinding a top quality dried hot whole chili pepper using a coffee grinder. I am not a coffee drinker, but you can easily buy a coffee grinder and use it for your hot dried pepper grinding as well as grinding your flax seeds.
In the diabetes dragon fruit salad meal, I use a heaping 1/4 teaspoon of freshly ground good quality dried hot chile peppers. In contrast, store bought dried chili powder required 1 to 1 1/2 full teaspoons to give the same amount of capsaicin.
Remember, for the same reason that using the ground chile powder or ground chile peppers makes it so much easier for you to digest and get the benefits of capsaicin for diabetes blood glucose lowering, you will also find that chile powders and freshly ground dried chile peppers lose their potency rapidly. If at all possible, try to grind only the best quality dried hot peppers and store the ground peppers for only a few days to a week at most.