Weapon set skill points, why use them?

Sorry fellas I'm a bit confused on this one, can't figure out what I'm missing.

I'm following a build that uses 1 weapon, it assigns skills to weapon set 1 for clearing and weapon set 2 for bossing.

There's a bunch of nodes in the skill tree that it says to use weapon set 1 (clearing) skill points for. For example 'increased movement speed, immune to hinder and maim'.

I don't understand why I would only want this on weapon set 1 when I could have it on both. What's the disadvantage here?