I see 22LR AR15's as great training tools, whether they be complete 22LR AR15's, uppers, or drop in bolt conversions. They all work off the same manual of arms. IMHO, the Ruger 10/22 encased in an aluminum Nordic Components body that appears to look like an AR is lacking as a training tool due to differences in the safety, mag release, and charging handle. As a plinker, the only thing that I see is different about it is looks and what accessories one can put on it.
Not sure about the complete rifle (iirc from seeing them at gunshows the Colt/Walther has a lighter feel to all operations and the safety would work out to the auto position on a centerfire variant) or upper only conversions, but the drop in bolt conversions don't work off the same manual of arms with the only thing really staying the same being the trigger.
FM 23-9 "Caliber .22 Rimfire Adapter, M261
Disadvantages. Some negative training aspects exist because of differences in the weapon's functioning when using the RFA. These differences include the forward assist not working, and the bolt not locking to the rear after the last round is fired. More malfunctions can occur with the RFA then with 5.56-mm ammunition, and immediate-action procedures are different."