Why does Serylda's Grudge still have 30% armor penetration?

After LDR and MR were changed to having 35% and 40% armor pen respectively, wouldn't it make sense to increase Serylda's armor pen to atleast 35%? Black Cleaver might still have 30% armor shred but that's armor shred, it applies to everyone hitting that target, making it far more valuable. This item genuinely feels cosmetic and even a lot of champions that seem like they would build this item opt for LDR or BC instead. It doesn't even scale off of lethality nor give lethality anymore. What's the point?