Yes, you can use a memory foam topper when camping if you want a comfortable night of sleep in the wilderness. It is not as good as an actual mattress would be, but it serves as a decent substitute if no other options are available to you.
Advantages to using a memory foam topper for camping
Memory foam toppers are great for camping because they conform to the shape of your body. This helps provide extra comfort and stability where needed. They also allow a person to create a sleeping platform without the need to carry something heavy or buy an expensive air mattress. You can also use it as a pad between you and the ground which will help keep you warmer than if you were on bare ground.
Another advantage is that memory foam creates an even surface that won't make noise when people are moving around on it like a traditional mattress would. You can also take it with you easily as they don't take up much space at all and they're lightweight enough to be carried anywhere, shape, or form imaginable.
Disadvantages to using a memory foam topper for camping
The downside of using a memory foam topper is that it won't provide the same level of support that an actual mattress would. You might find yourself more sore in the morning if you're not used to sleeping on a more firm surface. It can also be hard for people who are taller to get comfortable because the compression length is shorter.
Another downside is that they can be pricey and it's difficult to find them for sale around campgrounds or outside of retail stores. Camping supply stores will sell them, but they're often overpriced and you want to make sure you get one made specifically for camping use.
In conclusion, memory foam toppers are a decent way to get a good night sleep when camping. The negatives of it don't outweigh the benefits that it has to offer. You can also use them in conjunction with other things like sleeping bags and blankets to provide more padding underneath you while you sleep.