no, shift. It helps you highlight many files/folders at once.
Say you got a group of 12 songs all by the same artist all, same album. Highlight the first, hold down shift and click on the last. All in between should be highlighted.
From there head into File>Get Info, and you will be able to change the fields for all at the same time.
BTW, I did use a program called Corripio to find album art, but more importantly, locate the songs that didn't have album art.