While is it true that electromagnetism is stronger than gravity, gravity has special properties that make it important too. First, gravity interacts with anything that has mass, it's the only force that interacts with dark matter i think. In addition, it can never be deflected or blocked, unlike electromagnetism. Gravity has infinite range, like electromagnetism. Gravity always attracts, and never repels (except i saw a video by brian greene and the fabric of the cosmos that explained inflation as gravity repelling, but idk).