That means we have two banked regions for graphics ROM: 0xC000-0xCFFF, and 0xE000-0xEFFF. We probably want to bank switch program code, too; so why don't we ignore the /ROML and /ROMH signals complete...
Decoding the address bus directly also makes it trivial to overlay RAM on the screen matrix where we need to - for example, we might want a modifiable header or footer.
1