I think I can answer at least one of the questions, on why make 2.0 only C cables. When I got my Nexus 5X, I bought some assorted A to C cables to go with it.

I think I can answer at least one of the questions, on why make 2.0 only C cables. When I got my Nexus 5X, I bought some assorted A to C cables to go with it. I noticed that the 3.0-capable cables are awfully thick and heavy, and not so convenient to carry around with a mobile device. I bought some 2.0-only A to C cables that are much thinner, lighter, and more flexible, and use those instead. Considering that I will basically never need the extra 3.0 speed for connection to my phone, I'll take the cheaper, lighter, more flexible cable every time.