[piva00]

I use my phone with an external battery charging it (20800mAh power bank). It's cheaper and more useful to have a power bank than having a dedicated device for hotspot, the same battery can charge my phone, my computer and power any other USB device I might need.

I'm almost sure this is the main reason for these dongles to not really have a market. A phone already provides the same functionality, the battery drain on a laptop would be pretty similar (since the modem on a phone is very well optimised) so extra power through a charger/external battery would be needed anyway if the main issue is draining the phone's battery, it'd just shift to draining the computer's battery.