Primary vs. Secondary Categories: What Each One Does
Your primary category tells Google what kind of business you are before it looks at anything else on your profile. It is the single strongest relevance signal you control, more influential than your business description, your posts, or even most of your reviews combined. Google leans on it heavily to decide which searches you are eligible to appear in, and it also determines which default features show up on your profile, like whether customers see a menu, a booking button, or a service list.
Secondary categories work differently. They do not carry the same ranking weight as your primary category, but they widen the pool of searches you can appear in. A roofing company that also handles gutter cleaning can add “Gutter cleaning service” as a secondary category, giving it a shot at that search too, without pretending gutter cleaning is the main business.