Huh, I've had my car 10 years and didn't know that. Would this also be the place to connect a battery charger?
From another post I saw by Ken: Short story is "wherever it's convenient"
The whole idea behind any automatic battery charger is NOT to disconnect the battery. The electrical draw from the car is not a problem for the charger; that's what it's designed for. And you want to keep the battery connected so that the security system is enabled. So don't disconnect the battery!
The main question is where to attach the charger. There are three main approaches.
(1) You can attach it to the terminal post in the engine compartment fuse box and any nearby ground. This is easy to access, but may not permit you to close/lock the hatch (enabling the alarm) or to use a car cover.
(2) You can attach it to the battery posts. This is especially easy for an onboard charger (the one that's about the size of a videocassette), but it's somewhat inconvenient to remove the spare and reach down to plug in an extension cord draped along the floor. For external chargers, it becomes rather inconvenient to attach, and you may or may not be able to close the hood and cover the car.
(3) You can run a wire from the battery posts to a connector in an easily accessible location (such as just behind the front grille), and install a mating connector on the leads from your charger. This requires a little bit of work to install but once you've done it, is probably the most convenient installation to connect and disconnect, and allows the hood to be closed, the alarm to be enabled, and the car to be covered.
Incidentally, the recommendation in the manual for using the fuse box terminal is for jump starting the car, not for a battery charger. You can use it for a battery charger as well, with the advantages and disadvantages noted above.