It’s a pity they’ve shut down, though hopefully it can live on somehow as open source.
There’s a lot of activity in the Sketch/Figma/whatever to React space at the moment, including Hadron [0], Alva [1] and Lona [2].
There’s a real gap in the workflow between design - basically a drawing - and working code. Handoff tools like Zeplin help, but it seems redundant to build everything twice, first in a design and prototyping tool, then again in working code.
However I’m not sure where these tools fit in, as a team that uses React in production would have the skills - and would probably prefer - to dive in with code, rather than use the output of a code generator.
It’s meant to make things easier, but the tech is so complicated it’s way out of reach of those who might actually benefit from it.