Screenshot is from Windows where dotfiles aren't hidden by default. And all the lazy developers that created those directories, didn't bother to set the hidden attribute (See appdata is greyed, because it has the hidden attribute set)
Directories can have spaces in their name on other platforms too. On Linux, you can set the XDG environment variables to whatever you want, so eg. instead of using ~/.config for config files, you could use ~/My Config Files
Is it a good idea? No. Should every well-behaved app handle it? Definitely.