When should an advertiser consider leveraging below the fold(BTF)placements?

Advertisers should consider leveraging below-the-fold (BTF) placements when their primary goal is cost per acquisition (CPA). BTF placements are typically less expensive than above-the-fold (ATF) placements because they require users to scroll to see them, often resulting in lower visibility. However, this lower cost can lead to a more efficient CPA if the ads still drive conversions. For campaigns with an awareness goal, ATF placements are generally preferred due to their higher immediate visibility. While viewability is important for all placements, it's a specific metric, not the primary driver for choosing BTF over ATF when CPA is the objective.