I think 50% of it is simply another excuse to drop another $6k on a toy, and $20 a box for top end .22 ammo.
It's really a sliding scale of how many more reps does it allow you to get, and how close can you get your trainer to your centerfire gun to decide how much it will help your shooting.
I do think there are some valuable things about a 22 trainer, but I think the advantages are often overstated or at least not well enacted. First unless the gun is the same weight, same scope, same LOP, exact same bolt throw, same mag size, release etc. etc. you are forcing your subconscious to learn two sets of muscle memory skills. If there's one thing they beat into us at the olympic training center it's that the less change you have across your training the better off you are. Most shooters change their setup and technique far far too often to ever really evaluate if something is working or not. Building a 22 trainer to be a perfect clone of your centerfire is not going to be easy or cheap but it maximises the benefit.
Now good trigger time and reps are always valuable, but you can get those dry firing. Building positions training is helpful but again only if your 22 trainer is a 100% clone of your centerfire, and you can build positions all day without firing a shot. One of the best things dry fire does is allow the mind to decouple the shot sequence from recoil and noise of life fire, and allow the shooter to focus very intently on each step of their shot sequence without being distracted by the result of the shot. There are some things that dry fire is better than live fire even compared to rimfire. The best rimfire shooters in the world still dry fire way more than they live fire.
Now that said, if you live somewhere where you absolutely can't train with a centerfire much, but you can train all the time with a rimfire, then of course that's going to be more valuable than you not shooting. The same is true for NRL if you can shoot lots of local NRL 22 matches but only a couple centerfire matches a year, then of course shooting all those extra matches is going to be beneficial. So you really have to look at your situation and what having a .22 trainer brings to your training. There's also the benefits that simply come from more exposure to more shooters, the more matches you shoot the more likely you are to learn new techniques.
Wind calling I think helps, but they are different. I think what most gain is a 22 forces shooters to be more precise about their wind calls and that will pay off at longer ranges as well.
