I was a little surprised when I read this because it means the people at my local makerspace are magicians. There are tons of examples of curved stained glass as well as a lot of howtos on how to do it. The came glasswork page on wikipedia is full of stained glass with curves: https://en.wikipedia.org/wiki/Came_glasswork
What am I missing?
That said, I can see how a CNC approach could help with the speed of the process; shallow/simple curves are easy enough to do reliably, but deeper, more complex, and significantly concave curves require additional effort and planning, potentially a lot of manual work with grozing pilers to break out a concavity, and additional grinding to finish out the shape.
So being able to turn a machine process to some of those cuts would save a lot of manual effort and potentially get you right up to the final polish-grind stage in one go, which certainly sounds attractive for some kinds of design.
I've found a few instances where people have used CNC cutters with a diamond drag bit to help score the glass, and a few industrial glass cutting applications of similar to stained glass size items, but no real start to finish projects.
This is an interesting industrial example as they were able to produce a stained glass piece that is made almost entirely from curved pieces (a near impossibility with traditional scoring and breaking) - https://semyx.com/solutions/waterjet-applications/glass/
Industrial waterjet glass cutting: https://www.youtube.com/watch?v=a_qMKKwvzz8