I agree that it certainly isn't useless but you can only calm them once. After that, there's the echo that the animal isn't normally aggressive, so you have to kill them or leave, unless you were able to calm them while camouflage which is rare because most creatures see through camo. But, if you can calm them while camouflage then they typically aren't much of a problem anyway because you can usually just creep by them. And if you calm them while camo, it's permanent rather than temporary.

As to being a beastmaster and taming, there are very few if any mobs that are in hero range that can be tamed as pets. Most are 30's maybe low 40's, meaning they're not super useful in the end game. Still, I like the skill for it's flair.

On the other hand, it isn't the only ranger mechanic that is a little odd. Waylay/ambush is another good example because if you try to waylay something that can see though camouflage, you get the echo that they can already see you but the fight will auto initiate anyway in about 1 round which also doesn't make a lot of sense.