I'm unfamiliar with the variety of Mandarin spoken in Taiwan, so I was surprised to see a chilli-snack 香脆椒 referred to as 餅乾:
http://mall.tw100years.com/goods.php?id=9
真不敢相信這真是美味的餅乾!看起來是紅紅的辣椒,吃起來是香、脆外加點淡淡的鹹,不但能幫您排去宿便,還能養顏美容!
The definition of 餅乾 that I'm familiar with is biscuit or cracker, a baked pastry food. This snack doesn't fit that definition; it is made of fried chilli peppers: