I wonder if the meaning of the word "sightseeing" includes places for shopping?
For example, if someone asks me if I have recommendations for sightseeing, does it make sense to recommend a shopping center?
You would only use sightseeing with a shopping center if the shopping center were so unusual that it is someplace to see just for itself -- whether or not you want to buy anything. In most cases, that would mean no, you wouldn't use it for a shopping center.
The Queen Victoria Building in Sydney is apparently considered "the most beautiful shopping centre in the world" by Pierre Cardin, so if you're interested in Byzantine architecture, you might visit it for sightseeing alone.