Yes with Autocalibrate=2 then practice sessions can be used for learning, been a long time since I tried that so no idea if it works anymore but it certainly used too.
Each sim should focus on its own particular strengths. Before buying rFactor I thought AI racing was a thing of the past, especially after coming from iRacing. But when I raced the AI on rFactor it completely changed my opinion. Driving behind a car you could see it slightly driving off line or correcting its back end. The other benefit of AI is you can race the exact track and car you want, at any time, at any distance, and set the AI speed just a tad faster so you can get decent battles throughout the race and in turn improve yourself. Historic races have always been a niche and it's difficult to find online races (a perfect example is the almost always empty SSS GOOD OLD DAYS public server), AI fills that gap nicely. Over ambition, trying to more things right, often ends up doing more things wrong. AI learning the track is a key selling point, and something I've not seen in other sims. Certainly deserves perfecting.
Does it still work? I tried by setting "autocalibrate AI" to 1, I guess I'll try 2. It used to work...
