Hell no. No offense to any designers, but those who strictly stick to design and don't pay attention to what everyone else is doing, do not have a clue. Yeah, they make some pretty beautiful banners, but if you look around you'll notice that beautiful banners are not what's generating high CTR.
Even when working for a major company, my ugly photoshop banners with good sales text and effective call-to-action always murdered the CTR of the ones created by the design team.
