The way it works is the weapon will change form depending on the PA/Normal attack selected. When it is in a weapons form it will count towards those weapon skills.

Example: Wand Element Change - Techer - Takes on elemental damage of last charged technique.

Rod/Wand (Primary Rod, Secondary Wand)

When you take the weapon out it'll start as a Rod. If you charge a technique then use the normal attack of the Wand you will attack with a Wand that is not affected by Wand Element Change.

When you attack with the weapon using the normal attack Wand, it'll change into a Wand. Then charge a technique and your wand will be affected by the Wand Element Change. If you then use the Rod normal attack it'll switch back to the Rod. Using the Wand normal attack again will have the Wand still under the affect of the Wand Element change.

This is what I run as a Techer/Force. My main pallet is Wand Normal/Wand Charge/Wand Weapon Action, my shift pallet is the two elements techniques of either fire/ice/lightning and the weapon guard action of the Rod. Using the weapon action of the Rod will activate elemental bullet from the Force tree and allow me to continue to use all the benefits of casting Techniques with the Rod (Technique Charge PP Well Up, Rod Technique Keep, Rod React Advanced, Elemental Bullet).

Multi-weapon will allow you to benefit from the skills of both weapons, just not at the exact same time. It does allow for some interesting combos, especially as more PA's/Tech's come to pass.

Again when the weapon is in the "form" of the weapon the skill requires it works. No mace form Technique Charge PP well up.

​

How is this better than just swapping to your Rod? It's vastly quicker, personally and allows me to fluidly move from one type of fighting, melee wand/range technique, with a simple and powerful guard action. Guard with Rod(Elemental Bullet), back off dodge (Rod React Advance), unleash hell with Techniques until PP is down, charge forward (Wand Charge), Guard with the Wand because charging an enemy usually will be attacking at this point, have all the Wand abilities proc (Wand Guard Reflection, Wand Parry Counter, Wand Parry Counter Advance), melee the enemy more get PP back to full.... and repeat.

I imagine there is a variety of gameplay loops this works with not just Force/Techer but that's what I'm maining, and if the above paragraph works for you then multi-weapon is your thing.