Most rich civilization, to show off how great they are, have built monuments. Basically saying, look we are so rich we can redirect a big part of our society's productivity to building a magnificent piece of art. Notice, how the ancient Egyptians are remembered thousands of years later.

You should think of some research in similar ways. This is us saying, look how rich and powerful we are, we can devote a significant part of our society's productivity on discovering the very essence of this universe with no practical benefit to us. Detecting blackhole mergers is an intellectual monument.