文字列比較のみの if~elseif~elseif~が続く処理や、switch文での処理は冗長になりやすいです。
複数行の elseif を使う時は、連想配列でテーブルを使用するほうが、後で条件を追加しやすくなり良くなります。
参考 : Instead of writing repetitive else if statements -- Samuel Štancl -- twitter.com
✗ Wrong
if( $order->prodcut->option->type === 'pdf') $type = 'book';
elseif($order->prodcut->option->type === 'epub') $type = 'book';
elseif($order->prodcut->option->type === 'license') $type = 'license';
elseif($order->prodcut->option->type === 'artwork') $type = 'creative';
elseif($order->prodcut->option->type === 'song') $type = 'creative';
elseif($order->prodcut->option->type === 'physical') $type = 'physical';
if ($type === 'book') $downloadable = true;
elseif($type === 'license') $downloadable = true;
elseif($type === 'creative') $downloadable = true;
elseif($type === 'physical') $downloadable = false;
○ best
$type = [
'pdf' => 'book',
'epub' => 'book',
'license' => 'license',
'artwork' => 'creative',
'song' => 'creative',
'physical' => 'physical'
][$order->prodcut->option->type];
$downloadable = [
'book' => true,
'license' => true,
'creative' => true,
'physical' => false
][$type];