Were you dropped on your head as a child, then repeatedly smacked to ensure brain damage? That's like saying GTA is like COD because it has guns.
Battlefield is vastly superior and vastly better due to-
1) A modern physics engine with more destructibility.
2) Massive, sandbox maps.
3) Objectives that force you to be a team as otherwise you'll lose.
4) Naturally evolving games that turn players into a singular, organic force that commonly adapts to face new threats.
5) Vehicles.
6) Larger teams.
7) Actual skill is required to snipe players.
8) Pilotable, constantly spawning aircraft.
9) -blam!-ing Battlefield man.