Top works great for holding screws/bolts when you are working under the hood. Perfect place to put your beverage of choice on it while you are working on something too.
^ this. I love it. Normally I use the fan shroud but when I was doing intake gaskets I had that removed, the storage box was my mini work bench.
I keep several spare relays, fuses, brake fluid, and a pair of pliers in there.
Twice I've had brake lines blow on me, once I was an hour from home the other time about 6 hours.
Crimp off the line with pliers, top off brake fluid, bleed if necessary, and get yer arse home.