Custom post query by taxonomy

I’m slightly surprised that the first would work, because it’s terms, not term. Anyway, the correct way to do this is:

$args = array(
    'post_type' => array('product', 'comic', 'magazine'),
    'tax_query' => array(
     array(
        'taxonomy' => 'Genres',
        'terms'    => array( 'hot', 'home' ),
        ),
    'posts_per_page' => 10
);