I guess, it is matter of the meaning camping. For us, camping means walk-in camp, so it is more backpacking, when every piece of luggage is counted. Even thou, I know that in certain circumstances, tarp might be handy under the tent footprint, I never use one. I never regretted I did not have one. However, the common big tarp is a must for the rainy days camping, since only making an artificial house can make the bad weather disregardeable.
