Firearms training presupposes a purpose or goal when we step out onto the range. While most would agree that training with your firearm is an essential part of improving skills; without a method to track your progress or reassess your goals, training turns quickly into recreation. There is no purpose beyond punching some holes in paper or seeing if that watermelon really does explode as it does on video. We're not saying that it's not fun. It just isn't really training.
There's an old saying, "You don't win nothing for practice. You don't win nothing without it." Grammar aside, we agree. Practice means working on a skill. In any physical endeavor, there is no substitute for putting in reps. The arena of use doesn't matter, be it self-defense, hunting, or competition. The path from competence to proficiency to mastery is one that's sometimes solitary and sometimes shared.
Whether training by yourself, with a partner, or as part of a class each dynamic has benefits and drawbacks. But each has a place in skill developing.