They forgot the biggest downside: when you REALLY need to stop RIGHT NOW, you're not thinking about what kind of brakes you have. You're running on instinct, and that instinct probably says "do a grabby motion with your hands", but that doesn't work, and you don't brake on time.
Source: I have a bike with one coaster brake and one normal one. Have never intentionally used the coaster brake, have used it unintentionally many times.
I have a post-edit hook that asks the model if this edit introduced any comments, and if it did, remove them. This was the only reliable way to get it to stop that I found.
