Their page states that GRIN has no standalone creator product and no discoverable creator profile, and cites a tour of app.grin.ai as the source. That is the brand application. Creators have their own app, free to join with no follower minimums, where they browse brands, review offers, negotiate their own deals, and watch their earnings.
That is not a feature they missed. It is the other half of a two-sided marketplace, and it is why our creator data reflects program activity rather than scraped profiles alone. You cannot audit one side of a marketplace and conclude the other side is not there.