It's not really a waste of time, it's called doing it right as if you jump straight into something you can't do the basics of you're going to ruin yourself. We have a wide variety of maps today and they aren't all AR9 strictly. Man, it's the same as people saying "Oh just do AR10.3 240bpm as that's what the pros do" You can't just do that. Throwing yourself at a wall like that wont help in the slightest. Building up over time cementing your abilities and confidence in what you can do really helps to make you a better player overall. In the end you'll come out a lot more consistent at it.