OK, now explain ATM-to-the-desktop. Not what, but why: I know what ATM is, I just don't understand why I'd want an internal networking protocol designed to mix

OK, now explain ATM-to-the-desktop. Not what, but why: I know what ATM is, I just don't understand why I'd want an internal networking protocol designed to mix voice and data transmissions using short cells running right to my desktop. If we're going to do the 1980s Telco solution, isn't ISDN the service I'd get to my desktop?