The smart ones tend to have arrived at their belief after intellectual reasoning
What reasoning would that be, I wonder?
Let's look at it logically. Does human consciousness have a naturalistic basis? If no, then there must be a "creator". If yes, then there is no reason that we should not be able to create artificial consciousnesses. Once we accomplish that, then the next step would be to simulate artificial worlds with societies of these artificial consciousnesses, to learn about how cultures emerge and evolve, or just for entertainment. In the millennia to come, we will probably conduct billions of these simulations. In every meaningful way, we will be gods to these artificial entities, whether they believe in us or not. So what is the chance that we are the sole top level reality? Pretty small. So logically, there is almost certainly something out there. Maybe Jehovah, Jesus and Allah are just three teenage nerds getting their universe ready for their school science fair, so they can beat that Zeus guy that won last year.