How do Measure weapons work?

Solution 1:

Your premise on Measures is correct. These weapons essentially allow for bestowing buffs onto your allies without the use of MP or Items, but it is recommended to switch to a more effective weapon when you are finished.

Measures have low attack ratings, but ignore defense when used, damage being calculated solely on the weapon's attack. Measures also cause beneficial status effects on hit, so they are to be used to strengthen the party without using MP and should generally be switched out for more conventional weapons after being used

The damage calculated from Measures is low because ignores any stats and solely relies on the Attack Power of the weapon.

DMG = [Attack Power * Random(1 ~ 1.125)]^2

As far as Gambits, there are some guides, like this one, that recommend not setting gambits for Measures and manually triggering the attack on your ally. You will spend more time configuring your gambits back and forth for your different jobs. Since Balthier being your White Mage, you definitely want to use your Gambits for healing and reviving.

There are some Gambits though that could be used remove debuffs rather than apply buffs. One example would be

Ally: status = Slow

Applying Haste to a Slowed ally with the Caplier Measure will counteract the effects and will remove Slow without having to exhaust your White Mage's MP.