Both these are correct. If you wish to use it to measure a single phase load, up to approximately 18.3 A (4 kW @ 220 V, 4.4 kW @ 240 V) then you may include it, make sure you set it to the correct phase in the software.
If you do not use it, then no harm will come if you leave it enabled in the software, but it is better to remove it.
All the details are in the documentation that came in the Zip file where you downloaded the sketch.