Really? I haven't done a survey of Masterclass ads but I've had the opposite experience. Every one of them seems to be 90% highly-produced "inspirational" fluff with maybe one or two interesting one-liners that may or may not be bullshit.
Haven't actually taken a course myself. I'll admit their ads got me to check out their site given the big names they've managed to attract, so they did their job, but it looks like their programs are yet another "we'll sell you lectures with zero practical exercises or applications for $X/month so you can sound smart at parties" service.
I guess it might be useful for 17 year olds picking a college major or exposing people to brand new topics, or professionals already in the relevant field looking for tips, but that's about it. Watching Penn & Teller's Masterclass isn't going to teach you how to be a professional magician, Aaron Sorkin isn't going to teach you how to be a professional screenwriter, and Chris Hadfield isn't going to teach you how to be an astronaut or engineer. It's like paying $180 to read the back of the book of a profession.