The caps are there that you can practice without a pad on a normal table without reinzuhauen equal bumps.
On the go, the things are perfect, but the rebound ago not quite as good as a real pad and also a bit noisy (depending on the table). Therefore, a point deduction.
But who has to lug always place stand and pad?
I would recommend these things only highly if you want to warm up before Mucke backstage or gets in television long while.
Have fun with it
PS: My stoppers are, attached to thick poles, always in the desk ready, thus ensuring from time to time for small ne drum break at work (home office)