Your thumbnail decides your conversion rate before anyone watches a second.

Your thumbnail decides your conversion rate before anyone watches a second.
A "shocking face + red arrow" thumbnail pulls curiosity clicks — tire-kickers who never buy. A thumbnail showing the actual product, problem, or result pre-qualifies buyers.
Clickbait inflates views and tanks click-through to your link, because the audience came for drama, not a purchase. High views, dead description.
Qualify in the thumbnail or pay for it in your conversion rate.
Would you take 30% fewer views for 2x buyers? That's the real trade.