The perfect leg warmer doesn't exist oh, wait!
These check all the boxes and are a perfect way to extend summer bib shorts into colder months. I own some heavy, warm ones and a light pair from other brands. The heavy ones are overkill, don't fit well in pockets, are stiff, and have tons of seams. The light ones are more for sun protection, aren't very warm, are stiff, and have seams, but they do roll small for pockets. Both wrinkle and bunch up at the back of the knee.
The Castelli warmers are a perfect weight for matching summer shorts, are surprisingly warm, roll small, are soft, and don't bunch up or wrinkle at all. They are knit/woven like socks, so there are zero seams. For aero geeks, the zero wrinkles are nice.
Regarding heavier leg warmers, skip them and get proper bib tights. I used my big, heavy warmers on colder days, and while my legs were warm, I got uncomfortably cold hips. These Castelli leg warmers match summer bibs perfectly and keep you warm enough. If the temp is so low that they aren't warm enough, your shorts aren't either.
Here's a tip: when your skin is dry, all warmers will slide down. Rub a thin layer of Vaseline or similar where the top of the warmers will go and they will stay secure all day long.
If there's any limitation, it's that with no zipper, they are tight to remove over shoes. I wouldn't try it while riding. On the other hand, I prefer the light, zipper-free design. And they breathe well enough to leave on if you are going up and down hills and in and out of shade. Plan to remove them once, after the sun has warmed the morning chill.
They're so comfortable that if you like to wear shorts around the house but you're feeling a bit cold, they're not a bad option. And they then remind you that you should be out riding!
Thank you for your feedback.