It's not all taste, in the pastry world. Sometimes it just has to look pretty. And it has to be completely edible, even if you're not ever going to eat it.
And someone will try to eat it.
Chef Parks told a story about building a chocolate display box for a buffet line. A woman asked one of the servers if it was really chocolate. When he replied yes, she asked, "So you could eat that whole thing?" And when he said, "Yes, I suppose," she picked up the whole thing and took it back to her table.
They chased her down and got it back.
It's amazing what you can build with food. Especially sugar and chocolate. Most especially sugar. Here are some of the things I've built out of food.