Solutions based on third-party butts have essentially two modes: the usual, where everything is smooth, and the bad one, where nothing works and you're shit out of luck - you can't get to your data anymore, because it's in my butt, accessible only through that butt, and arguably not even your data.
With on-prem solutions, you can at least access the physical servers and get your data out to carry on with your day while the infrastructure gets fixed.