The difference between Hidden and Dormant hosts, is that Hidden hosts are based on an admin action, whereas Dormant is 100% automated.
This also means that a Dormant host that becomes active, will be revived automatically, whereas a Hidden host requires an active admin action.
Whenever possible, rely on Dormant hosts, it‘s much easier.
All hosts will stop counting license wise after 45 days, if they are inactive. Hidden hosts will stop counting license wise within 24 hours.
Note: Per policy we accept temporarily exceeding the license count without additional charges when e.g. replacing a large number of devices, despite the old devices remaining Dormant for 45 days.