Tell me about cycling rain cape. I'm looking at this one

https://www.cleverhood.com/products/...c-houndstooth/

Most of my commuting is on a fendered drop bar road bike, riding 17-24 mph with a backpack. A smaller part of my local riding is on an fendered Xtracycle cargo bike, grocery bags in the panniers, riding 15-18 mph. The weather is rainy, rainy, rainy.

Will a rain cape over normal clothes keep me dry? Compared to rain jacket + rain pants + booties? Will it slow me down (aero or otherwise).