It was never dead to begin with ;-D
To quote from another place,
""it's complicated" as it depends a bit on who you are.
retrogamer? It can run other emulators, and it can run libretro cores. On linux it can also hijack other games (redirect audio,video). There's recording, streaming, customized analog filters, led controllers and all other kinds of bells and whistles and some of the other weird stuff that the video shows where it acts as a complete desktop environment.
arcade cabinet / htpc user There's a theme ( "gridle" ) specially for this category of users, navigation / configuration etc. can be done entirely with a gamepad. The usual round of filtering (title, year, game family), 3d models, specialized options for vertical oriented games or cocktail setups. You can show things either as customized layouts (built in editor) or through the default 'grid of video snapshots'. There's also support for networked extra displays and network controls.
developer / pervert Run multiple emulators in parallel, feeding them the same input and see how their outputs differ?. AI experiments for automated gameplay?, multiboxing?, playing several games at ones with the same input? plain old game development? Programming something like the usual "list + images" kind-of launcher in it shouldn't take more than a few hours.
I use it for all of the above."