If you do something decoratively, you do it to make a thing or a place look pretty, not because that extra bit has a real job. Fruit might sit decoratively on a cake; wood might be carved decoratively on a box that still works as a plain box. You meet the word more in writing about food, crafts, and design than in chat. Though actually, decoratively does not mean beautifully. A thing can be done decoratively and still look busy, cheap, or too much. The word only tells you the purpose was looks, not use. Compare a handle placed so you can hold the bag, and a handle placed decoratively so the bag looks fancy — one is for the hand, one is for the eye. In speech, people often just say 'for decoration' or 'just to look nice.'

裝飾性地、作為點綴（為了好看、不一定實用；不是「很美地」）