I think they are so comfortable, but I always hesitate. My mom had a cape that I used to borrow, but it's floor length so definitively too costume-like for me now. I think capes are excellent for when you're being driven around by someone else. Like so many things; high heels, fitted clothing etc! But I get frustrated because I don't see the practicality for daily life. As soon as you reach your arms out to drive the car then you're cold, and since the only handbag options are hand-carried, again you need to have your arm somewhat outside of the cape.
Another item that is so beautiful to my eyes but also so impractical are coats with 3/4 length sleeves. Jackets are a different story, but if it's cold enough that a coat or a cape seems like a good idea it's also cold enough that I want my arms to be covered all of the way. I know you can wear long gloves, but am I really the only person who ends up taking off my gloves all of the time to do things?