When I think of an easy, crowd-pleasing thing to bring back from Taiwan, sun cakes is a good pick because it does not need much explanation when you hand it over. Biscuits and dry breads are good because they survive the journey and are easy to share at work or with family. I would look for it in a proper local supermarket, covered market, deli, pharmacy, gift shop or small producer rather than leaving it until the departure gate. Back in the UK, it is worth checking specialist shops first because they often stock a better version than a broad marketplace listing. I would rate it higher when it is locally made, clearly labelled and easy to use at home, and lower when it is just tourist packaging.