What's the point of the garbage collector

SqlConnection connection = new SqlConnection(FROM_CONFIGURATION)
SqlCommand command = new SqlCommand("SomeSQL", connection);
connection.Open();
command.ExecuteNonQuery();
command.Dispose();
connection.Dispose();

class MonkeyGrabber : IDisposable {
   public MonkeyGrabber() { /* construction grabs a real, live monkey from the cage */
   public void Dispose() { Dispose(true); /* releases the monkey back into the cage */ }
   // the rest of the monkey grabbing is left as an exercise to grad student drones
}

class MonkeyMonitor {
    public void CheckMonkeys() {
        if (_monkeyPool.GettingTooRowdy()) {
            MonkeyGrabber grabber = new MonkeyGrabber();
            grabber.Spank();
        }
    }
}

using (SqlConnection connection = new SqlConnection(...))
using (SqlCommand command = connection.CreateCommand())
{
   ...
}

using (SqlConnection connection = new SqlConnection(FROM_CONFIGURATION))
using (SqlCommand command = new SqlCommand("SomeSQL", connection))
{
  connection.Open();
  command.ExecuteNonQuery();
  command.Dispose();
  connection.Dispose();
}