A use case of a vacuum can be described as a specific way in which you use your vacuum cleaner in the household. A few use cases of vacuums include:
Remove dirt from floors.
Clean up messes off the floor.
Clean upholstery or drapes.
Smoothen out or fresh up the carpet.
Once you learn how to use a vacuum, you'll find that it has many use cases beyond that of cleaning floors. Some vacuums today also have built-in mopping functions that clean up spills.