Extra POI databases?

My new Nuvi 2555LMT is my second GPS replacing my three or four year old Magellan GPS which died. Both units come with a POI database that contains restaurants, filling stations etc, Why would I need other POI databases? I searched through a couple of lists of additional ones but the one installed for free has those POIs. I never updated either database on the Magellan because the update was almost the same cost as buying a new unit.

BTW do the map updates include an update of the POI database from Garmin?