Deploy sensors per site, group devices logically, and get one consolidated view across every location.
Each site needs its own sensor so local traffic and flow data doesn't have to route across a WAN link just to be polled.
Use Groups to organize devices by site and by role (core, edge, access), so alerts and dashboards can be scoped to a site without hiding the enterprise-wide view.
Create a top-level dashboard rolling up status across every site, then let each site team build their own scoped view underneath it.