We deploy stabilizing jacks fore and aft of the trailer's tandem axles for the following reasons:
When one of us gets up to go to the bathroom, or wakes up early and walks to the kitchen or living room, the whole trailer moves with every step. This wakes up the other person who is still trying to sleep. Neither of us are particularly pleasant when awakened before our time.
We festival camp a couple of times a year, which means we're packed in tightly with other RVs full of friends. When we engage in... "adult activity", the trailer bounces and shakes and rocks enough that we get teased mercilessly by everyone around us.
Both of these problems are solved by the stabilizer jacks. They remove 98% of the trailer's motion.