I'm not sure why you asking this since your code clearly demonstrates that it does work. return accepts any expression. The only question might be one of precedence.

Does
  return $value ? $value : 'none';
mean
  return ( $value ? $value : 'none' );
or
  ( return $value ) ? $value : 'none';
?
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If you're not sure of the precedence, a simple test will tell you. (Again, you already did that, so I don't know why you are asking.) Either way, you can state the precedence you desire explicitly using parens.