Urinals are built against a wall because it's a easier target for urinating, hence easier to clean. Additionally, it takes up less space. Wall-mounted urinals are the best urinal choice for public areas because it's more possible to maximize any bathroom's occupancy.
In small spaces, wall-mounted urinals allow more individuals to urinate at different locations simultaneously instead of waiting around. This helps make using the bathroom more efficient and less time constraining. Wall-mounted urinals also make it easier for individuals to hit their targets because they descend to the floor. This helps maintenance staff tremendously, because wall-mounted urinals allow people to make fewer messes.