Benefits of practicing with a .22lr vs just dry firing more

Learn how to shoot really well prone.
Learn how to build stable position
Learn how to build multiple positions under time
Learn basic strategy for wind (I made a whole thread on this).
I have enough experience now to truly understand that Dthomas3523 is spot on in his assessment of the order of importance in training that most-mid pack shooters should be thinking about. Also, practicing with a rimfire will absolutely help you improve all the above^^^^^ with much more trigger time at a fraction of the money. The money is not just a function of ammo it's match fees, travel, gas, food, etc etc all substantially more in CF matches. Also, and this has been stated before, be wary of the free recoil trap that can come from too much focus on rimfire.