Yes. a visibility thing. I'd rather see the road ahead for myself whenever possible rather than rely on someone else to react in a timely fashion to anything that might happen. Someone who might be on his/her phone, having a row with a passenger, cuddling a dog or otherwise distracted. Of course it's not always possible on single carriageways but when it's possible to do it I will, I don't see anything wrong with it and yes, I do the same with any large vehicle obstructing my view of the road ahead. When safely possible of course.
Given the choice of being able to see the road ahead or not being able to see the road ahead, which would you choose?