Amazon Ads has updated the Brand Store quality experience so ratings (High, Medium, Low) are based on sales attributed to a storefront rather than visitor dwell time, adding peer sales benchmarking and sales-impact optimization insights.
Read more: https://advertising.amazon.com/en-us/resources/whats-new/brand-store-quality-rating-now-reflect-sales-performance/?ref_=a20m_us_wn_gw