Yeah, that sidebar is mostly wrong, bu fighter types can benefit from delaying. Both for the "don't get in the way of the god wizard's opening spell" application and the "let him move up so you can get the first full attack" (I prefer to ready to attack and then 5 ft step away triggered upon him ending his move, so he gets hurt, is denied the ability to hurt me, and if he doesn't using any remaining action to back off, ALSO suffers a full attack from me before he can act again; but thr principle's the same) Veekie mentioned can both be helpful in many situations.
Even as a caster, I can see delaying in certain instances, though more often I'd ready. For example, a save or lose spell that gives a new chance to end each turn like Hold Person. Cast that in the middle of someone's action, and rob them of that turn and get your next turn before he can act again. And of course you want to delay using it until the party fighter is already in melee with the guy, to facilitate coup ge gracing.
Rogue....ONLY if the foe is immune to sneak attack is delaying till after they act ever justifiable, and even then, it's basically only because you're gimped for the encounter and nothing you do is lkely to matter much anyway, may as well stay back and not die, at least.