Common Lisp actually lets you use any string for an identifier if you wrap it in pipes, though you have to be a bit careful of casing in that case. Still for so many characters on the keyboard it's not needed to wrap which is so convenient as you illustrate.

    (let ((|hello world| 3)
          (|HELLO world| 4)
          (|こんにちは (jp)| 5)
          (|pi\|pe| 'piped)
          (|newlines
            work
            too| 6))
      (list |hello world| |HELLO world|
            |こんにちは (jp)| |pi\|pe|
            |newlines
            work
            too|))
    
    ; --> (3 4 5 PIPED 6)