For what it's worth.
BMW are probably using PolyFuse in order to provide a resettable fuse. This means that if someone puts on whatever type of contraption and get a short, simply pulling it out and turn off ignition will reset the output.
The downside is that a Polyfuse emits som internal heath whenever in use, and if you need higher current draws, it needs a bit of cooling effort, such as extra wide track and space on the circuit board. Given that the chosen plug type (DIN type) is a small current type best suited for phone chargers, small external lamps etc, items with a bit heavier load is best of avoiding the DIN type plug. (Yes, I know, a small air-pump will work with a DIN plug. But it may get warm if used for a while).
Used as intended, the Aux power output works great. But if you need heavier electrical load, hydraulic output for your farming gear or a winch, this is not standard equipment, and extra outfitting will be needed.