There is something wrong with this component, from the way it is presented is should be in the same group as the other (24 armor/ +20% resistance/ fitting stat) ones. But it does look like it was left behind.
Where other ones give 20% resistance, this one gives only 10%.
Furthermore, where others are used in all armor, this one is limited to chest, shoulder, focus/shield.
Finally, to beat it down even more, no one will pick the 10% pierce up over the 18% pierce + 18% bleeding resistance superior Silk Swatch for usage in chest and shoulders.
This leaves us only with focus/shield, which pool also has a lot more better components to choose from.
My suggestion would be improving this component to the +20% resistance category and make it usable in all armor with that.
Usually I put +Armor components into Belt, because it’s the only slot where it matters, but since I typically cover pierce/bleed res. with Legplates of Valor+Silk Swatch, I would almost never put a %piercing resistance onto belt (I didn’t even knew you can’t put resilient plating onto Belt until you mentioned it). So yeah, would be nice to be able to, at least.