I've been a commissioner salesperson for years before I graduated from college. Our highest commission items by % were in this order.
1. Extra Warranties.
2. Accessories.
3. Product.
Reason? markup. For every $100 you spend on a warranty the company expects to profit $80. Because products generally don't break (ignoring x360's early years).
I have never and will never buy warranties, since the money I save by not buying them is more than the rare case when I am forced to repurchase a broken product.