Why? You keep repeating this without ever defending your argument. As of right now, and in the near future, more Mac users have USB-A. There is simply no compelling reason to make this change unless you absolutely need extra features provided uniquely by USB-C. And this device doesn't need anything like that.
The reverse problem (I have lots and lots of USB-A devices, while the only USB-C device in my house is my wife's Android phone, so like almost everyone else I had "no compelling reason" to want a device with any USB-C ports, let alone only USB-C ports) didn't convince Apple to leave one or two USB-A ports in their pro macbooks, unfortunately. That you can't go buy a current macbook and current iphone or ipad and connect the two when you get home unless you buy extra stuff, but you can if you have an older macbook, is silly. It is a point in favor of that "Apple's greatest MacBook Pro yet: the 2015" joke/actually-true-thing, I guess.