You can't beat a good tent carpet can you... you're camping so you're probably cold, dinner isn't fantastic and when you wake up in the morning, whatever the weather, the inside of your tent is likely to be covered in condensation!
So having just a few things to make you more comfortable is hardly a crime and a carpet is the best place to start! No I wouldn't bother taking it with me if I was having to hike with a tent, but for car camping it's ideal. Takes up hardly any room and just takes the chill off the ground, whilst making the whole tent feel more inviting.
This particular carpet fits my Coleman Instant 4 Tourer just perfectly, is thick enough to be pretty hard wearing and thin enough so that you can fold it back inside the back when you're done!