I agree it is not always useful when comparing between positions. Sometimes it can be good to break it into guard skills and big man skills. But it can still be a useful shorthand for thinking about trainees. Typically single position trained players will get 10-13 pops in their first season, and then that number drops by a couple every year as the player ages. Knowing that, and knowing the average quality of players at given total skill point levels, you can kinda estimate if a potential trainee might be worth your time.