Video Demonstration!

With flash, like what is used on VOXL, removing power while the kernel is writing will result in corruption and bricking of the board. It can happen during development when a lot of changes are being made on the board and then power is removed.

To prevent system partition flash corruption:

• run poweroff before removing power: $ poweroff -f
• Use the /data partition for file storage

Linux has a setting for how often the flash is committed to reduce the risk, but of course there could be different side effects. You can see a writeup on the topic here, as it is common in all of this type of single board computers

Your smartphone fixes this by making you press the poweroff button before shutting off power and does not have a removable battery.