I'm pretty sure it was one of those things that sounded like
The Future of Dimming® at the time, but in practice very few people were willing to pay the substantial premium for what turned out to be a very minor benefit. If they had caught on more widely, then I suspect most of the issues would have been ironed out over time. They are far more complex than a D20, and the
power components (can't remember offhand if they used MOSFET or
IGBT...) are just inherently less robust than a big ol'
SCR.