What were the main motives and goals of World War 2 battleships?

The PURPOSE of a battleship "was" to fight "on the battle line" AGAINST another "battle line" of battleships, from another nation (country). Ship of the (Battle) line was shortened to "Battleship." Battleships represented their respective countries. In the US, we named them after states. US Cruisers (the next biggest warships) were named after cities. US Destroyers (the smallest warships) were named after US Sailors or US Marines. Aircraft Carriers were a NEW WEAPON; those ended up being named after Revolutionary Battles, such as, "Yorktown", "Lexington", "Saratoga", or famous Revolutionary War fighting ships, such as the "Wasp", or "Hornet." Battleships were like heavy weight boxers, all big gun and lots of armor; designed to "slug it out" with others of their own kind. Battleship FLEETS never had the opportunity to fight as "DESIGNED", that is, in a decisive fleet action, except once: The Battle of Tsushima, on 27 May 1905. WWI was missed opportunities & WWII was dominated by the aircraft carriers.