According to documentation the flag authorization.admin.usage in /dspace/config/modules/usage-statistics.cfg should control the UI behaviour like this:
When set to true, only general administrators, collection and community administrators are able to access the pageview and download statistics from the web user interface. As a result, the links to access statistics are hidden for non logged-in admin users. Setting this property to "false" will display the links to access statistics to anyone, making them publicly available. ( Taken from: https://wiki.duraspace.org/display/DSDOC4x/DSpace+Statistics#DSpaceStatistics-ConfigurationsettingsforStatistics )
Instead of above behavior the statistic buttons in the UI are displayed always to everyone regardless of the flag or the fact being an admin.