Mikes suggestions

assets/js/base/context/hooks/payment-methods/use-payment-method-interface.ts

@@ -91,7 +91,15 @@ export const usePaymentMethodInterface = (): PaymentMethodInterface => {
 						} );
 						return store.hasPaymentError();
 					},
-					isSuccessful: store.isPaymentReady(),
+					get isSuccessful() {
+						deprecated( 'isSuccessful', {
+							since: '9.6.0',
+							plugin: 'WooCommerce Blocks',
+							link: 'https://github.com/woocommerce/woocommerce-blocks/pull/8110',
+						} );
+						return store.isPaymentReady();
+					},
+					isReady: store.isPaymentReady(),
 					isDoingExpressPayment: store.isExpressPaymentMethodActive(),
 				},
 				activePaymentMethod: store.getActivePaymentMethod(),

assets/js/base/context/providers/cart-checkout/payment-events/index.tsx

@@ -65,8 +65,12 @@ export const PaymentEventsProvider = ( {
 		const store = select( PAYMENT_STORE_KEY );
 
 		return {
-			isPaymentReady: store.isPaymentReady(),
+			// The PROCESSING status represents befor the checkout runs the observers
+			// registered for the payment_setup event.
 			isPaymentProcessing: store.isPaymentProcessing(),
+			// the READY status represents when the observers have finished processing and payment data
+			// synced with the payment store, ready to be sent to the StoreApi
+			isPaymentReady: store.isPaymentReady(),
 		};
 	} );