I think there's no point in having quick replies if they behave in the same way as buttons. From a UX perspective it makes more sense to see them disappear after click. That way, they're different from buttons, which stay in the UI after click. They both have their uses and this is also how they behave on FB Messenger. At the moment the quick replies stay in the UI after click in the cognigy webchat. I hope you will update this feature for better UX.