I agree that there's no real storage: maybe you find places for some bits of wiring, fuses, that sort of thing.
However, you can remove the screws holding the seat on and throw them away. I've had a single bungie looped over the back of my seat for many tens of thousands of miles, and that (plus the fact that there's often a small duffel or other baggage strapped there) holds the seat in place under even the most dire circumstances. To remove, I just pop the bungie off and lift the seat. Saves a lot of frustration and time.
Others have used H.D. velcro to hold the seat in place. Same basic concept. And if you insist on leaving it bolted on, at least use a hole saw to drill out the plastic side covers so that you can access the seat bolts without removing the side covers first.