HotSpot Whitelist is used to specify the computers which should pass through HotSpot without authentication. Such computers are not listed on the main page, and their usage is not tracked.
The Whitelist can be used, for example, to let your IP cameras communicate without login procedure. You can also whitelist some of the computers which should be accessed remotely.
HotSpot uses IP whitelist and MAC whitelist to define which computers are allowed to pass-through without authentication.