High value low engagement versus high engagement low value apps
Most mobile apps, and websites to an extent, seem to be driven by how much they can get the end user to use or engage with them; the more usage the better.
However for some apps and websites there is a more useful way to look at their success. These apps provide high value with each interaction but expect significantly lower engagement from an end user. These are the apps or websites you use/visit for very specific scenarios or to complete very specific tasks.
There are mobile apps that allow you to build a mesh network using nearby phones running the same software in case the internet fails. If you need to use this application it potentially provides very high value but it is one that you probably hope you never have to use - so very low engagement.
What3Words is an application that can provide very high value by identifying an accurate location for use in specific scenarios however most users will not use it regularly. There are likely to be a set of apps on your phone or websites you occasionally visit that provide this high value low engagement benefit.
Not all apps and websites should be measured by how much you use them; some should be measured by the value they provide when you need to use them.