It's absolutely ridiculous, but it beats holding the diffuser for the hour of dry time! I do still have to go in at the root with a diffuser, but everything else dries adequately. So no, it doesn't reduce drying time for curly hair, but it gives you the freedom to go hands-free. I take the liberty to apply my nighttime routine; you can do your makeup, but keep in mind that the strap will get in the way if applying makeup around the jawline.
To diffuse, I flipped my head down to get all the hair into the cap. I first did the drawstring and then the strap. (It's all necessary because it will fly off or not contain all the air if you don't do both.) I did add a claw clip at the top of my head before I flipped my hair to add volume, and it didn't get tangled once I turned on my hairdryer. I do have a shark, but I imagine it would work with any basic hair dryer, if anything, just tape that sucker on and it should hold.
For curly girls: Keep the setting on high to maximize airflow and keep it cool if possible, so you don't get frizz!