And that they are for good looks makes no sense because those people who become monks do so seeking purity and not good looks, and the plain brown black and gray of the monks 'shoes are not especially beautiful anyway.
假如是為了美觀，也不然，一來出家只求潔淨，不講美觀；二來僧鞋的黑、灰、土三色都不是頂美的顏色。