Toilet paper is produced in a way that makes it very easily disposable. Different from making use of other heavy products that may clog up your drainage system, toilet paper is usually very light. It is thus easily passed through the drainage system, especially when used after urination or defecation.
There are people who use water for washing their private parts following defecation. However, in areas where there are limited amounts of water for most parts of the year, then using toilet paper is the best option.
Toilet paper, particularly when marketed like luxury, might come with several useful extras. It can be embossed, colored, patterned, perfumed or medicated using anti-bacterial compounds. Some varieties of toilet paper are also naturally treated using aloe.
While the toilet paper is very useful in the current world, it has some shortcomings also. For instance, it is very costly as you require purchasing them regularly.