As background, style insensitivity was introduced so that codebases can use a consistent camelCase or snake_case regardless of the style used by upstream libraries.
Well, maybe not writing. Occasionally low-level C libraries - especially those that deal with keyboard input - decide to provide identifiers differing only in case... There's a WIP RFC for providing a way to deal with identifiers that need to be verbatium by surrounding them with backticks, though.