Most operational satellites do for station keeping in order to maintain the proper orbit and to move them out of the orbit after their useful life so other satellites can take their place. Depending on the orbit some are deorbited and come back to earth; otters are boosted up into orbits that aren’t used.

The issue is everything in orbit is technically a satellite and there’s are tons of junk up there from rocket bodies and formerly operational satellites to debris of all types including from Russia blowing up one of their satellites a year or two ago, leaving hundreds of pieces of various sizes orbiting the earth. All of which need to be tracked to so as to avoid collisions with objects currently in space (ISS and other satellites) or to be launched (you don’t want to lose a $1B satellite by launching into a debris cloud.