Large format cameras are usually view cameras that use single sheet film in film holders, which means that a number of actions needs to be taken between pictures - the fact that it is not as easy as inserting a roll of film results in a more contemplative photography style.
Large format is still popular for some applications because of the higher quality of large prints, and because most large format cameras have adjustable fronts and backs that allow the photographer to better control perspective. Ansel Adams made extensive use of this effect.