I would not get the 22 conversion for training. I would get it to practise marksmanship at a much lower cost.
You fight like you train. With the massive differneces is recoil you will not be prepared for using your weapon.Your recovery and follow through would be way off in a fight.
Having said that you could do training drills run through with the 22 in place to keep the cost down. Then do several drills with the normal pistol to get used to the recoil and doing mag changes.
I personally would not change anything but I reload so the cost is a lot less.