Paintings in general help make a room look less dull. Consider a particular kind of room where there is furniture and white walls, for instance. A painting of something as beautiful as a Caribbean beach, for instance, is enough to enrich the entire outlook of the room. Even a minor picture of a beach, or pond, or stream in something such as a library, for instance, is something which seems pleasant.
You may recall occurrences of people possibly bidding even thousands of dollars for a particular kind of painting. Having one in your house could help serve as a conversation topic for guests. It can be something they find appreciating to look at, and for relatives to see as well. Decorations have traditionally been used by people in ancient times as well. The kinds of designs you might see on what was once a royal person's clothing show the probable appreciation of art that even people years and years ago had.
One of the interesting things about how a painting is made is considering how difficult it may actually be to make important details appear well with the usage of a paintbrush. One might wonder how the person managed to make a few if any mistakes while having tried to combine specific details together with drastically different colors. And how one mostly avoid accidentally painting over other parts depending on the size of the brush. It is especially impressive if a person managed to paint a good picture with reasonable details in a short amount of time.