Stun Vs. Silence

[Sephirah]

So I just learned Spirits Within and haven't played around with it much yet, but I noticed it's off GCD, and my biggest gripe about shield bash is missing interrupts because it's on GCD. So my question is, does silence pretty much do the same thing?

Edit, just doing my own testing while questing it doesn't seem to stop any of the moves from going through, unless I'm not using it right? Disappointing, this makes the 2nd time I've been disappointed by Spirits Within... (Don't get me wrong, I've come to appreciate that movie for what it is, but at the time, when it was released in theaters, right after playing 7/8/9, it was totally a letdown, lol)