My answer is: No profit/benefit.
Hence, nobody believe something that cannot be proven to be true.
Actually, this is a very good question that often arise in the mind of an atheists. A very good question because.. Often, atheists get lost into thinkings finding answer to this question.
I really like this question because there's certainly something to be gained by NOT believing in claims until any evidence supports that belief.
BUT, what's the purpose behind believing in something that cannot be proven to be true? People unnecessarily dishonor theists.
Beliefs are very important. When all the facts are not known, we patch the gap with Beliefs. If Beliefs did not exist we would lock up just like my old computer when all the facts were not known.
I see no difference between theists and atheists. One believes God exists. One believes God does not exist. The only difference is the belief.
Science and Discovery so often start with a belief. The next step is to search for the truth so the facts can be known. Beliefs merely point a direction by which one should search for the real truth. Beliefs are the start of the journey and not the end.
Sometimes beliefs can be hard to prove. If one claims the belief can not be proven, does one really care about the truth by giving up on the search? I do not think so.
I think atheists and theists provide a great service to each other. They widen the view so that a larger picture can be seen. Perhaps together they can Discover the Real truth in time.
Throughout time, brains win. Further, there is always expanded thinking in front of us all. There is always more to Discover. Perhaps, one needs to be brave enough to venture into undiscovered country along with the effort it takes regardless of the time. One just might be surprised at what is capable of being Discovered. If we wait for others to do all the work and all the Discovering, the wait will be much much longer.
Is it really about Truth? How badly does one want the Truth??
That's what I see. It's very clear!!