You missed where massive armies were Traveled thousands of miles a whole bunch of times, especially in the last four books. But no big. :)
My point was that if Traveling were available here, for instance, small bands of commandos to take out command and control of the enemy would be infinitely more efficient than large armies.
While I’m aware that this tactic was employed in the book, to my mind it would completely make the large army meaningless.
Large armies confronting each other on a battlefield implies positional warfare, which would make even less sense in a world with Traveling than it does in our world of armored vehicles and helicopter-borne raiding parties.
You may have noticed the remarkable disappearance of large massed armies clashing. There’s a reason for that: They tend to wind up being just really large targets when faced with a technologically advanced enemy.