GQ factory centre console. Why did Nissan design the bottom like this??

Hi, I removed my centre console to give it a thorough clean and just noticed this recess in the bottom of it. It's hard to describe in words so I'll add a pic for you to see what I'm talking about. Anyway I am curious why Nissan built it like this instead of making the base completely flat. It almost looks like its there for a specific item to be fitted but I'm stumped to what it could possibly be. So if you have any info or ideas or even a guess please post a replyAttachment 82023

Could be for rigidity or tool design or simply so your marbles collect in one place, ready for your next game?

I´ve seen on the net a Patrol for cold countries where there is a backseat heater over there. So the center console hides it and the only usable space is further up on the console, like, shallower. Could be one of the reasons (multiple applications)