The simple answer is, a lot of it is marketing hype, and if you prefer using your hands to wash your face, that's good enough.
There are going to be some studies (inevitably funded by big brands) that show that it cleanses your face better, but ultimately, there's no study I've come across that proves that it will improve your complexion.
Do note also that these devices can be too harsh for senstive skin - so definitely stay away if you are prone to eczema or redness. It’s even possible to have first-degree burns from overuse or too-aggressive cleansing.
