The casinos I've been to were as much theme parks as they were gambling houses; simply walking around in them taking in the atmosphere was an experience in their own right.
Most pachinko parlors by contrast hardly have any room. There are rows of pachinko machines with small stools in front, and there's barely room to walk around. It's just you and the machine in front of you, and all the noise; careful not to bother the guys sitting either side of you. I'd say they are very different from casinos outside of their gambling nature.
I'm just pointing out that pachinko parlors can (and do) appeal to Japanese folks in ways that westerners might not appreciate.