https://pay.amazon.co.uk/blog/how-amazon-pay-addresses-cart-...
https://pay.amazon.co.uk/blog/how-amazon-pay-addresses-cart-...
Of course they need to tell a story about increased revenue to the retailers, because otherwise why would they voluntarily give Shopify control over their relationship with their customers?
If I am on my phone, I am more likely to complete a transaction if I can just hit the Shopify Pay button. If I need to complete some form that looks like it is from the early 2000s, I might wait until I am in front of a computer, by which point I may lose interest. (There is a lot of middle ground between these two extremes though.)
Similarly, I am more likely (when there are multiple alternatives) to revisit a merchant that uses Shop Pay because of the reduced friction.
(I don't doubt the 75-85% figure, rather the $1T one.)