Apart from Acorn machines (which I love by the way, but not as much as Ataris)and my Mac Classic, there are no other real computers that boot their OS and HCI from ROM. That's a real plus because I'm always deleting important system files.
It's like why I still use my Mac Classic, the OS is stable, there's some great software, and I'm not lining Gill Bates' pockets (except when I use Word for MacOS...oops)
And I defy anyone to show me a better keyboard than the one on the Mega ST.