The use case is to have a web browser that does not have time limits. This would be needed for example in school where the teachers expect that children can use their mobile phone browsers for information seeking. Currently it is impossible as a parent to foresee how much time the child will need for schoold use.
Another option is to allow other browsers to be used alongside SAFE browser and let those have their own time limits just like any app. This would of course let the user to browse any content but that should be the parents' choice to make.