Tier lists can be useful for the purposes of a very short guide if that is their intent. For example, when I first started playing FE, I looked up a FE7 tier list just to see if the characters I liked were any good, or worth using. I didn't need to know how to use them well, or any tips, just whether or not they could be. So I looked up near the top, saw Raven, and gave him a shot that I might not otherwise have given him.