A 5th wheel RV is designed so that most of its considerable weight is borne by the tires, and in turn the axles. While each corner of the box portion of the camper has what is usually called a stabilizer jack, these are not designed to hold the weight of the camper or to lift it off of its tires as a jack would. They are meant to be used to stabilize the unit after it has been leveled, and to assist with front to back leveling but only in small amounts. The idea of adding a tripod that extends from the 5th wheel hitch plate down to the ground is to stabilize even more, and to keep the whole place from excessive swaying and shaking when people are doing their usual things inside of it. That's the theory, at least.
In reality, there are pros and cons about these devices. Some people use them, and others say they don't have a need for them. Some RVers believe that a tripod is better to have than nothing under the front end of the camper - it just doesn't feel right without the landing gear down. They are relatively inexpensive, ranging from $60 to close to $200 for a tripod. It takes close to 15 minutes to set up the stabilizer once you have everything else done and ready. There. no installation, you just use it when you need it. Since it folds up and is relatively lightweight - 25 to 45 pounds or so - it doesn't take up much of your precious storage space.
On the cons side of the discussion, many RVers who have tried tripods say they really don't work as expected - they still allow movement. And as mentioned, there are those who say they don't see a need for the devices. Another drawback is getting the tripod set up on non-level surfaces - it isn't as simple as on a nice level concrete or gravel pad. And it seems that adjustments made for non-level sites cancel out the stabilizing effect, because the tripod becomes loose and shifts with the weight above it. Storage space is always needed, and it's just one more thing taking up room that could be used for something else. Not to mention that you could buy a half tank of gas or so for the price.
There are a range of tripods available for your camper, but the main differences are in being steel or aluminum, and the related weight capacity. I don't know about you, but an 800 pound capacity doesn't seem to me like a lot for something like this, so it's probably better to spend a little more and get a stronger - and heavier - tripod stabilizer.
Ultimately, whether you really need one need or not depends on you. Do you use your camper on rough ground, or mostly level spots? Do you have lots of family - that is, kids - running around and causing the other inhabitants to get sea-sick on dry land? Maybe it's just the tow of you or even just you, in which case you might be able to get by without it. At any rate, it looks like one of those optional pieces of equipment that RV owners love to buy and try, then decide if they actually like it or not. If you don't, you can always sell it to someone else to try.