These stoves are very cool in concept, but sadly they don't produce enough power to be worth it to carry on a trip over an extra power bank.

I was looking to maybe buy one of these some years ago, but decided against it after reading this review https://www.tek.no/test/i/awyyzE/prosjekt-gjemmekontor-dag-5 (Review is in Norwegian but you can translate it.)

In the review he talks about that it is difficult to keep the fire going because of the small size of the stove and after 1 hour of burning he only got 29% percent charge on an iphone 5. So it is not really worth it when a power bank is smaller, lighter and cheaper.