It makes no sense to use it on scalars.

Hey, that's not such a bad idea. For conditional inclusion in lists, instead of something like:

    @foo = (
        ...
        ( $include_bar ? 'bar' : () )
        ...
    );
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you'd have

    @foo = (
        ...
        grep( $include_bar, 'bar' )
        ...
    );
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