in regards to all simulations being unreal.. There are certainly levels of unreal-ness. Especially when you are using a plastic pistol that weighs about the same as a bagel. Things in the real world are not going to work out the same when you use that muscle memory to articulate a 2 pound pistol that has actual recoil.
If you're training for a life and death situation, I'm hoping you would go for something better than the cheapo $10 WallyWorld springers. It's like saying "You depend on firearms to save your life?
You mean one of these things that will more than likely explode in your face and kill you?"
If you drop some money on your training tools, then you can get an airsoft gun that is for all intents and purposes a real gun that doesn't kill what you shoot with it.