FYI, on MacOS, it is a property of the partition, so you can reformat and have a case-sensitive filesystem. Applications may subtly break if they weren't tested on such a filesystem, but I had used one for several years without too many issues.
This has mostly been useful for working on shared repositories where, say, a Linux user (or other user on a case-sensitive filesystem) pushes two branches, say `feature/foo` and `feature/Foo` which works fine for them, but on a case-insensitive filesystem, git gets very upset.