Will the werewolf's Howl of Terror ability still be useful at higher levels?
Much a like the 'Dismay' shout and the Nord power (which i never used) the 'Howl of Terror' will have an effect throughout every level in the game.
Note that that the spell tome which also has this effect will later have no effect as you level up.
If you wish to boost smithing or any other skill i suggest you do this late on as your combat will be less effective throught higher levels when enemies get stronger. (DONT CHEAT) :)