To add to AlotOfReading's point, many places have some electricity, just utterly unreliable.

It might be down a few hours every day, or completely cut for days after storms or infra degradation, or the current fluctuate too much for delicate electronics. Many places could also get hold of a gasoline generator.

These kind of variations could require more thinking on the design, but being able to use electricity when available and hand power when needed would be the best.

Ideally the people on the ground thinking about their specific issues and having open ways to adapt the machine for it opens the door for many kind of evolutions.