Hyperspace is an idea accepted by many or all theoretical physicists who studied the subject. The concept of Hyperspace is that there are more dimensions out there than the 3 dimensions familiar to us together with time. Theoretical physicists favour 10 dimensions for reasons that ordinary readers are unlikely to understand. These extra dimensions exist in our universe and may explain phenomena like gravity and light. 
Well the real world is complex and difficult to understand. By contrast Bronze Age and Iron Age mythology is easy to understand, after all early people wrote them. That can make religion appealing to simple minded people and children.
The reality of science can inspire us with awe and wonder, we don't mythology about gods and monsters to inspire us.