I'm currently learning the arpeggios. I'm wading through the various 7s at the moment. After checking I am understanding the intervals I am practicing each arp shape in every key. My question is... I am finding that I csn look at the diagram and play without looking at the guitar. It seems to help me get a feel for where my fingers should go and makes my ear more keen as wrong notes really stand out. However, I read that one shouldn't do this for some reason, I'm not sure why? What are people's thoughts on practicing in this way?