I knew that ancient architecture was usually vividly painted, but it didn't occur to me that the statues might be as well. The interesting thing is how nowadays we model buildings and statues after our notion of what classical art looked like, but the models were never intended to look like that. It's almost cargo-cultish, in its own way. Of course, the non-color elements like the shapes and the proportions still stand through, and those are definitely worthy of study. But painting such a sculpture or building like this would probably be outright offensive to some people.
The color-restored versions somehow look less... impressive with the colors on, but that could be just because I'm used to thinking of the colorless versions as more regal. On the other hand, black-and-white photographs look more artistic as well, so it could be something about the lack of color itself.
If you want to see how ancient classical buildings looked when they were in use, check out the old British TV series "I, Claudius." It's strange to see everything so bright and garish, but it's accurate in spirit, if not in detail.