If you want to become proficient with the center fire caliber, and practice for its use, then an understudy with the same grip and trigger makes a lot of sense. Too, if you plan to teach your wife or GF how to shoot, a .22 lr is a good caliber for all the obvious reasons.
I've used .22 lr understudies for the .45 Automatic for 30+ years with good success...besides the uniformity of grip, controls and trigger, the .22 allows use of a handgun when noise constraints may preclude the bigger caliber.
For those who, pooh pooh the soft recoil of the little .22, remember that skill with a handgun is predicated on a uniform grip, laser focus on the front sight for sight alignment, and a good uniform, shot to shot trigger release. All of these can be learned on a .22, at a fraction of the cost, and usually with superb accuracy that builds confidence.
Here are a cpl pics of my Ruger SR1911 with a Marvel .22 lr slide mounted...and the proof of the pudding! That's a 10 yd group, shot from a Weaver Stance...and the first mag full after installation. The 2nd shows what the gun is capable of with the full house .45 ACP slide...BTW, these were some of the first magazines fired with the then new SR1911.
Best Regards, Rod