When the customers navigate to the store to browse and buy the products from your online store, they will see the “BUY IT NOW” button on the product detail page. By clicking the “BUY IT NOW” button, the customers will directly navigate to the checkout page.
But, if you have enabled the switch of the Hide Dynamic Checkout Button (i.e. BUY IT NOW, PayPal, or GooglePay) from the product details page, the customers then can process the checkout from the Cart page only.