The ancient Romans were practical people. They wanted their art and architecture to be as practical and useful as possible. They also wanted it to be beautiful, but only if it was practical. So a great deal of their art was used in the construction of the architecture they built - in their buildings, baths, temples, road signs, and homes. Concrete is a ancient Roman invention. They used concrete in structures to make them strong. They placed designs into the concrete area, if any, that was visible.
They were also realists. When the ancient Romans created statues, they tried to make the statues look like the subject or model. If the subject had a big nose, the ancient Roman artist would give the statue a big nose. (The ancient Greeks would never have done that. The Greeks loved beauty for beauty's sake. The ancient Romans loved beauty that was practical.)
The Romans are famous for their mosaics, which were made of bits and pieces of colored ceramic tile. Their artists put these pieces together in breathtaking beautiful ways. But the tiles were also practical. Mosaics were used on floors and walls and hallways and entry ways to not only beautify but to strengthen. They were also easy to wash.