Powerful chakra=/=lots of chakra.
Also, Itachi didn't use Amaterasu five times. He used it once, used it again which set fire to the trees because they spread based on his line of sight, and then used Kagutsuchi on Sasuke. Yata Mirror also wouldn't consume chakra as it is a spiritual weapon he holds with Susano'o, not a jutsu.
Summoning a Crow Clone and summoning a crow aren't that impressive either, especially the latter being something Kid Naruto could do with his chakra disturbed by Orochimaru's seal on top of Minato's.