For students visual astronomy is one of the best ways to bridge the gap between classroom science, "party trick" science exhibitions, and real world research in a way that inspires awe and a desire to learn more. It's a way of turning the night sky from a beautiful mystery into a source of knowledge and excitement.
For teachers visual astronomy is a way to put material learned in class into real world context. Whether it's studying gravitational interaction via star (or galaxy!) clusters, or nuclear fusion via direct observation of the sun, astronomy can put a tangible "laboratory" to concepts otherwise impossible to study hands-on (short of taking a field trip to Los Alamos!).
Astronomy holds significance in all fields of science, however it may be of special interest to those exploring the fields of Physics or Chemistry.