Humans like to believe in different concepts because their brain is curious and wants to find out answers about something that is unknown.
Once they come up against questions that can't be answered by science or any other theory then they tend to come up to their own conclusions mostly based on what they believe in or whatever their imagination lets them decide in the end.
This is where religion comes in. A lot of people who don't have faith in their own imagination will want to follow somebody else who is convincing enough. Thus, following a religious messenger etc.
So the point of religion is to serve this basic need of human beings in believing or following something that they can't quite understand.
A believers answer:
Since there can be so many deviations and so many concepts regarding what could be the unknown, how the universe came into existence, Who made it all.
Also humans only ponder about these questions for a while till they engross themselves in worldy activities.
So there was a need to guide human beings. So that they come to realize the true identity of their maker. So that they can come close to Him in one way or another.
Thus God decided to send guidance upon his men by choosing some people out of themselves whom He blesses in order so that He can make them a blessing for others. Who would then use their knowledge and grace given by God to enlighten others.