The panhard bar is such a wonderfully simple design that gets a bad rap from a long history of poor implementation.
Having too much lateral axle movement can be particularly troublesome on an air suspension equipped vehicle, because of this, it's easy to see who so many people prefer to avoid using a panhard bar. The reality is that a properly designed panhard bar system can keep lateral axle movement down to a very acceptable number.
For example: on a suspension that has a 30" long panhard bar and 10" of total wheel travel, the axle would move less than .21" off of center at its extremes. And that movement goes down to .155" using a 40" long panhard bar with the same 10" of travel.
Sure, watts-links look cool, but they don't always fit in the confines of a rear suspension and are unnecessarily complicated for most vehicles.
Half Travel vs. Ride Height video - https://www.youtube.com/watch?v=4yJin88G5Qg&t=78s
Sagitta video - https://www.youtube.com/watch?v=zRSYxlohSdY&t=13s
Sagitta calculator - https://www.mathopenref.com/sagitta.html
Book order page - http://www.airsuspensionbook.com/shop/