I’ve had a few clients talk to me about their emails not displaying properly on mobile devices and one of the first things I tell them is more email is read mobile than on a desktop email client. So if they are not designing their emails to render properly on a mobile device they are not putting their best foot forward.
In today’s email world (desktop, tablet and smartphone) emails need to fit the screen they are being delivered to and provide the user with a good experience. The impact of using responsive design when it comes to email is exactly as one would expect. Higher click through rates, opens, engagement, etc!!