Basically like omecle said, because you can mow through things at a lower level so fast, you dont get a real grasp for your job in all situations. Although one can never say low leveled monsters can represent the difficulties of the ones at the higher levels, the lower leveled ones are the building blocks for you to take the stronger ones so you dont become some idiot like i seen some people do..I doubt they are actually idiots irl but from what they do they should have learned 10 levels ago..basic things...if you cannot learn basic things then why would you do well at the higher levels where people dont power level you and things need more precision(that and if you #$@% up you get more whiplash)?