Amazon's brand-protection and brand-tools programme, free with a registered trademark. It unlocks A+ Content (which lifts listing conversion 3-10%), Brand Analytics with search-term and market-basket data, counterfeit reporting, your own Brand Store, Sponsored Brands eligibility, and access to Project Zero and the Transparency Program for item-level authentication. This is not optional housekeeping: if your product gains traction on Amazon, knockoffs are a when, not an if. Enrol before you list, not after a factory is already selling your design at half your price on your own listing page - and register the trademark early, because Brand Registry depends on it.
Benchmark. The test is timing: trademark registered and Brand Registry enrolled before your first listing goes live, with budget set aside for ongoing brand protection. If you are selling on Amazon without it, you have no real tools against counterfeiters.