They are leveraging the connotation of "buy" to get you to give them money. If they used the words lease, rent, or borrow or explicitly stated the purchase may

They are leveraging the connotation of "buy" to get you to give them money. If they used the words lease, rent, or borrow or explicitly stated the purchase may be for a limited time then consumers' brow would furl as they pulled away from the action button. That is bad for conversion. This is classic anti-market behavior.