Most programming languages don't have significant whitespace, but it doesn't prevent people from writing readable code in them. And I haven't ever seen anybody write a long JSON config any differently - it's indented etc, for the same reason why C code is indented.

Still, editing JSON directly by an IDE that still exposes its syntax is "editing by hand", just as editing C in Vim with ctags is still editing by hand.

I do have to note though that VSCode uses JSON with extensions. Most obviously, it allows comments. But there are other minor things that make it easier to write (and parse) - e.g. it allows trailing commas in literals.