Present power chargers are without any extensions, but it can charge and discharge. And most of these power banks are with many different shapes & style. The package is most stylish & flexible.
Portable power charger is using USB input and output, charging by an external charger to plug into a computer USB interface, then it can charge for the product itself.
Regarding folding charger, the AC plug can be plugged into a household socket to charge.
Power bank is much convenient and easy carry. So it is used very commonly in the daily life.