It also enabled nxhosting, which was magical --- allowed one to do remote control over dial-up (so long as one didn't manipulate too large a pixel image).

I really wish Display GhostScript had gotten traction w/ the GNUstep folks.

On comp.sys.next.advocacy Mike Paquette talked about how he might not have stayed at Apple after the NeXT acquisition if he'd realized that that first decade was going to be a re-tread of his first decade at NeXT (writing Quartz vice writing Display PostScript) which I think really understates how important that code is.