Just like any other accessory, you're gonna get various opinions based on experience & usage...
Being a solo-RVer, I've never felt the need for one since I don't feel the effects of my own walking around in the rig. The only time I really notice any 'rocking' is when my washer/dryer combo is on the spin cycle, or in high-wind situations. However, I've been inside of other rigs with more than 2 or 3 people/kids walking around, and felt they could've probably benefitted from something to stabilize things.
Now, I don't know it your rig has them... but what I have done is added some stabilization to my hydraulic leveler jacks by way of the use of Anderson Trailer Jack Blocks.
Initially I got a pair of these to use as cribbing to replace some cracked wood blocks I had... but discovered while using them to added benefit of how much they helped stabilize the rig by shortening the stoke necessary for the jacks. A shorter stroke (extension) meant less 'flex' of the jack legs, which translated into less movement of the rig. I've then bought enough for all 6 jacks, and have been using them for almost a year now. The built-in magnets make them easy to apply to the pad before extension, meaning I never have to walk around adjusting & readjusting them as I level up. And since the pads fit exactly into the recessed area, they'll never slip off like I seen happen on other rigs using those lego-style square blocks.