This does translate into the real world, if developers use the flags. I know their babel plugin uses some heuristics to auto apply some of these things, but its extremely conservative.
The flags themselves are available in the real world though and can be used to achieve high performance.
Its really a shame Inferno never caught on the same way as other frameworks. Its extremely fast and intuitive, and had a nice take on functional components (just add the lifecycle methods as props, instead of introducing what is now React Hooks, though I think Inferno is held back not having a hooks API for some level of mindshare and compat there).
Even SolidJS hasn't quite crept the performance Inferno has managed to achieve.
EDIT: If memory services, the creator of Inferno works (worked?) at Meta (Facebook) as well. For whatever reason, it never garnered mindshare at FB either, despite arguably being a better solution than React in many real world scenarios and coming around at roughly the same time. I have always wondered what the story was there