I also installed the supports. I must admit that I've been disappointed. The supports do stiffen up the table, but I've found that the plastic "plug" or insert to be a bit fragile. Mine broke almost immediately. Now, I do set up and take down my table almost daily, and I do USE the table, but I don't believe that I'm overly rough on my equipment.
I've always thought the supports should be (1) incorporated into the table design as an original part, and (2) be designed to be more robust. The supports seem to me to be an after thought.
Dan