Except it does block specials. It just doesn’t block CC.
You can block Oscar’s airstrike by looking up for example.
The only thing you can’t really block with shields are things that originate from the ground, like Thorn’s DoT field.
Combined with Shield-Poking he does around 700 DPS at level 10. By the time you deplete his health to where the boost offered by the helix is less significant, you’re either dead or an axe throw away from death.
I wasn’t exaggerating when I said he makes mincemeat of anything he can touch. He is literally uncontestable in duels once he reaches 10 and once the enemy catches on to his damage (and isn’t stupid), his presence alone provides plenty of suppression because nobody’s gonna want to engage him.

