[anonlastname]

I could see it being useful for when you want an easy way to get a high voltage spike out of a 5v power supply. For example, if you wanted to build a board for igniting the gas in a potato gun that ran off of a USB power bank.

[semi-extrinsic]

Then you want something like one of these instead:

https://www.ebay.com/itm/DC-3V-5V-Arc-Generator-High-Voltage...

You also want to use the gas dispenser from a Paslode impact gun, an air mattress inflator and a Zodiac check valve for the air purge.

[TeMPOraL]

Speaking of power banks, what would happen if you plugged this device directly to one?

[vortico]

Only one way to find out!

[huseyinkeles]

most power banks don't have the data lines, and as far as I see this device uses the data lines to destroy the host. So I'll guess nothing would happen.

[londons_explore]

You could design one which did destruction via the power lines if you wanted to.

That's much harder though because power lines tend to have big-ish capacitors on them.