I have found that motion, when needed, can really help. IN the picture, notice a string from around the toms neck, under a stick to keep the string, low profile, and then back to the blind. A few tugs on the string, can bob and spin the decoy. Has worked well.
I have used many different methods to give my Decoy's motion over the years starting with strings attached to them. Had a track that was spring loaded to spin and move my strutter, also a couple of different battery powered devices one of which was remote controled. They all worked at times and did not at other times.
IMHO they are just added expense you do not need and a real PITA to haul around and setup so I have stopped using all od them.
Agree on the motion, that can sometimes be the difference. 2 years ago I had a tom hung up at 300 across the field and wouldn't budge, I belly crawled to my tom decoy and took it off the stake and started crawling towards him. He came unglued and I shot him at about 5 yards.
Check your state regulations before you use something for decoy movement. I believe it is illegal in Michigan. The only motion allowed has to be derived exclusively by power of the natural wind. That means no strings attached.
I use pretty much the same set-up Paul uses. I put two eye-bolts in the ground and run the string through the eyes and back to the blind. Attach string front and back of the decoy. You can see it here in this trophy pic. He struts perfectly with a little actuation of the strings. As Scott mentioned, it has killed a bunch of late season educated public land turkeys. The picture here was of a bird killed mid-May on the most heavily hunted piece of public land in eastern SD. Hardly called to him, just used the motion to suck him in.
My setup is similar to Brotsky’s and Paul’s, with a little different twist. I attach some Fireline or similar fishing line, that is spooled on a small spinning reel, to a small eye screw attached to my deke. I push my decoy stake into the ground at a slight angle, parallel to my blind, so that the decoy always ends up spinning back forward, facing uphill and broadside to the blind. (if that makes sense). By doing that, I only have to attach one string to the deke to be able to give it movement. I run the fishing line from the blind, under a small stick or two, to try and keep it close, or on the ground.
I run and gun alot. For years I have used nothing but a cheap, small black umbrella, that I open up and hide behind. At times I can open and close slowly, to get their attention. Then I got fancy, and painted on a white circle and red top, and some brown to duplicate wings,,,,, it allows me to get up on them, "sometimes" cheap and easy to use.