At times an adventurer may find himself far from the life of convenience that spurred his great journey. In those moments of unfamiliarity one may find the amenities of life to be long distant memories and they themselves in great need of simple modernities.
In the middle of a desert, breathing air too thin to even retain the heat of my breath I once found myself in need. Inside my room made of stacked salt blocks, the compass/thermometer attached to my bag said -8° C. There were no power outlets, no climate control, nor anything save a small, elevated light in the darkness. A bare bulb hung above a room housing two preposterous buccaneers who stared at it with hope in their eyes, and dead batteries in their hands.
In this moment, far from any civilization and in need of power, perhaps you will have the luck (more than foresight) to have one of these little devices in your kit.
Many places that I have been fortunate enough to visit and survive do not have infrastructure such as the city provides. Where a single generator runs the lights for certain hours of the day and no accommodation is made for charging pleasantries, you may find this little device to be a savior.
In the day of smart phones and charging bricks, we are both more and less susceptible to crippling power loss. Consider tossing one of these light bulb adapters in your pack before you go. If all you have is a light bulb, you can now charge your phone at the furthest flung stopover in your meanderings.
Pro Tip: Check the voltage for the country you are in 110/120/220/240! and check the voltage rating on your power adapter for the device you are trying to charge. I nearly killed myself with an electric razor once!