[mbrookes]

When development of v1 started, JSS was the only solution that (with some tweaking) met all the needs of component library (as opposed to say, an application), as well as being one of the most performant.

The thread that this comment[1] is in is where it all starts, but the repo and presentation linked from that comment should give the answers. At least as a snapshot at that point in time).

[1]https://github.com/mui-org/material-ui/issues/4066#issuecomm...