Hi, Andrew welcome to the forums.
there is a school of thought which believes that many mutations that happen are not harmful or beneficial, they are neutral or extremely close to neutral. This may have lead to increased speciation, as a large number of neutral mutations may cause one population to not mate with another population.
However, Zebra stripes are actually beneficial. A simple google search of the term "benefits of zebra stripes" pulls up this article (
How do a zebra's stripes act as camouflage? | HowStuffWorks ) which explains that zebra stripes are effective camouflage against savanna predators and works well for confusing them when zebras travel in large groups. They are also useful for finding mates.
I understand you are new here, so I will give you some advice. I recommend you do a little research on something before asking questions(A simple google search would suffice), that way you don't end up making false claims and can make a much clearer post.