« Isolation pad reduces booms and vibrations »

This is a pad that can isolate a guitar amp from vibrating throughout the room. There are other ways of doing this, like using chairs and stuff, but those are still technically flawed. Isolating the amp so that it rings throughout the room without touching the floor is an ideal way to get a good sound. Vibrations in the floor can limit the tone significantly and really muddy up the low end of your signal. Therefore it is good to have some sort of separation from the floor so that you can prevent this from happening.
I think that this is one of the cooler things you can buy to help get a better sound. It's really cheap and it'll do a lot to prevent uncessesary loss of signal. Listening with this will give your sound more low end clarity and less unnatural resonance, both of which are beneficial to sound. Another good thing about it is it opens up new spots in the room to put an amplifier. It'll allow you to get closer to spots that would vibrate when the amp is placed on the floor, places that were thus unavailable before. This opens up room micing opportunities a lot.
I would say that it's functionality is pretty limited, but it's also a pretty cheap piece of material. If you don't have a good sounding room already, you're probably not going to benefit much from this piece of gear. However, if you own a studio and you want to get better sounds out of your amplifiers, I think that this would probably be a fine choice and it wouldn't be too enormous of a purchase. It's one of those things that you wouldn't necessarily need but can definitely improve your sound.