Imagine yourself without the use of your legs or lower body. Think about the performing the simplest tasks and how much harder they would be. Using the bathroom would be near the top of this list. This is why having a grab bar in a handicap restroom is so important.
A grab bar provides a handicap person with a point of leverage from which they can assist themselves on and off of the toilet. Upper body strength takes over the responsibilities that we take for granted in our lower bodies. With a grab bar, the job is still tedious, but far easier than without a grab bar.
If you have a restroom that provides handicap access, having a grab bar is the most basic of needs. Be sure to provide at least one grab bar, depending on the design of your restroom, for your handicap guests. Just go back and imagine yourself in the same position if you ever wonder why again.