It sounds as if zoning only can hurt me not help me?

Not so. As an existing owner, you would look to the local zoning rules to protect your property values and peace of mind should

your community want to rezone to build a new prison, a raw sewage pipeline, or new highway; or

your neighbor be planning to build a second story that blocks your stunning view of the ocean, or wanting to start a pre-school in her home or car repair shop in his garage; or

a company wants to reconvert the neighborhood gas station to a McDonalds, which is going to up the decibel level and traffic in your otherwise quiet neighborhood.