On-device storage lets you store information specific to the current user that does not need to be shared with other users. It is available offline without needing to call a back-end system using the internet.
Examples of the type of data that could be stored on-device are:
- Personal settings/preferences for the app
- Temporary data that is not ready to be sent to a back-end data source
- Data to allow offline use of the app
- Data only related to the current user
The data is stored either on the device (for mobile apps) or in the browser (for web apps), but the most important thing to remember is that the data is only available to the current user since it is stored on their device only.