I think they're way useful.

Let's look at an invoker, for example:

wilderness <1021hp 432m 901mv 22360tnl (-18.31%)>
A thunderous roar shatters the air as a rain of boulders pummels this place!
You narrowly avoid the falling stones.
Arkellin fades into existence.
You dodge Arkellin's shocking touch.
Arkellin absorbs the force of your smash with a lightweight suit of gold chainmail.
Arkellin absorbs the force of your stinging lash with some leggings from the snow worm.
Arkellin absorbs the force of your smash with some leggings from the snow worm.
Arkellin is covered with bleeding wounds.


That's a lot of damage avoided.
Shield block also isn't the only way to up those skills, and when they're high %'s, they're very useful. It's basically an extra parry/dodge - why wouldn't you get it?

And there's an easy way to up the skill for orcs in specific :->