Bridging the Gap Between Believers and Skeptics
That is a big question with many answers since there are many benefits of knowing God.
But in the main, if God created humans for a purpose, we have to know God by way of what God revealed through the Messengers in order to know the purpose for which we were created and fulfill the purpose of our existence. That purpose was revealed by Baha'u'llah.
There are certain things about the Baha'i Faith that really attract me. Labor as a means of worship. And the spiritual development of man being another. The fact that even your prophet says they'll be someone to eventually replace him and usher in another, more advanced spiritual age for humanity. There are a number of things I don't like about this religion too, however. The fact that there is no clergy and monasticism is forbidden. And honestly, even though the religion promotes unity, I feel as if it won't really do too much for the overall unity of our species, because even though it is but one religion, all it really did was create another schism in the Islamic world view.
I reject the reason why I exist is to know God. That's trite and too simple. Instead, I try practicing my own divinity by being resourceful and being generous whenever it is appropriate to be so. Knowing the Messengers may be how one person understands the Abraham, and in return, the Baha'i God, but rather I intend on trying to exemplify divine attributes and characteristics while I'm alive so I and my loved ones can have the best life possible during my short time I am here. Life is too precious to constantly be reciting prayers and quoting scripture and we should learn and love to live life instead by enacting own our divinity, especially the generosity between oneself and others.
That may not be the reason why you exist, but that is the reason why I exist, and know that God exists, too.