I use a pair of aluminum jack stands just in front of my wheels and under the frame when we are parked long term. I have considered putting
scissor jacks there instead to make it easier to deploy them for short term stays of a few days or so. My good friend and former moderator of the Travel Trailer forum, Les Adams, did just that and was pleased with the results.
Yes, they do make the trailer more stable and reduce bouncing a bit. Does not get it all out though. The only way to do that would be to take all the weight off the suspension by blocking up the whole frame.
Another good friend of mine has the JT Strongarms installed on his 5th wheel. He is very pleased with the stability they provide.
Barney