Like everywhere else, they are times and places where decoys would likely be helpful when hunting the mountain Merriam's of the west. Sticking a decoy or two in the ground in front of you is probably not going to hurt your chances, but they are very often not necessary.
If you like to hunt by sticking your decoys in the ground somewhere and waiting for a gobbler to wander into range to see them, then that kind of hunting out west is generally not a very productive method compared to an active "run and gun" or "search and destroy" strategy. However, if you hunt by proactively looking to find gobbling birds, set your decoys out once you find one, and then try to call them into visual-contact range, they can most certainly be an aid.
If you want my advice as a western hunter, I would tell you to hunt without the decoys for a while. I think you will eventually find that you enjoy hunting that way more so than by lugging the decoys around and/or sitting over them watching the weeds grow. Over the next ridge you may find a gobbler than is perfectly willing to come to your calling, with or without the dekes.
