This is a generalised surfacing tutorial explaining techniques. He did split2 as a demo, but decided he didn't need it. It doesn't look like he has a specific design he's trying to create, but is modelling 'on the fly' while explaining the techniques he is using.
I agree with Bjorn, but will leave to possibility open that the Split Line2 will be used in the next installment of the tutorial.
It just makes sense to create the split line (for later use) at the same time that the other (Split Line1) was made.