Frankly it looks good to me and I see the seatstays as more of a style pick.
With Tour magazine style testing with a lower body only dummy they might have a negative aero impact, but IRL with you pedaling constantly and the dirty airflow around your legs the impact should be minimal. It's a bit similar with aero seatposts, IRL less important than people think (they still have an impact) and the added comfort of a round seatpost is something that most people should value higher.