Yeah I would say the newer WARs that just get Inner Beast sometimes struggle with not using that cooldown right away because at the same time they have to learn managing wrath stacks. As they don't have Infuriate skill yet so the IB cooldown isn't available anytime and that is a first for them. Also, not so out of the ordinary they are sitting at 5 wrath stacks all the time, or they are letting them fall off which is very bad. Sometimes I'll help them out and if I see they are sitting on those 5 stacks tell em to use IB in the pull. It'll jive, and they can take it from there.

Inner Beast is 20% mitigation, 300 potency attack and self-heals based on the damage it does. If they are in in current gear and going with a good of amount of STR the healer can notice a bit of a difference even in a small pull with just that CD alone. In the meantime they can pop Convo, Foresight, and use Bloodbath to self-heal while hitting things. But using IB as much as you can early on is a good practice to becoming a good warrior

Warrior cooldowns is why we can go practically full STR with good gear, play finesse mitigation and healers noticing the profound difference over a full-VIT one that doesn't use cooldowns.