No such thing as dumb questions...'cept the one never asked...
The divider keeps them from becoming 'mulch' from going through pumps and filters or being burnt by the heater. Also, keeps them away from the aptasia and other things on the LR that could hurt them while they are smallish.
Basically, they live in a barebottom tank on the left. All of the mechanical and biological filtration, plus heat is on the right.
Dave