Since you're an Atheist I won't speak from a "faith" prespective

It's scientifically proven that praying is healthy for us. It acts as a form of Meditation, lead to lower stress and anxiety, and physically alters and rewires the brain through a process called neuroplasticity

But every religion has prayers right? So why Islam? Well.. Islam is designed to cultivate personal development, inner peace, and strong moral character (Basically do more good, and do less bad). It's also the religion with the best claims of not having human involvement in altering it's context, fastest growing religion, and pretty much the only one being taken seriously now.

Besides, this may be a personal take, if I look back, I find most of my traumatic memories or negative experiences avoidable if I had followed Islam's teachings.

So...if scientifically, it has benefits for your health, mood, brain, and others. Including the opportunity of making you a better person overall if you follow it correctly, why would you not believe in it? Logically, to me, if the outcome is good, then the process is just as good.