I have nothing against Lightning. It introduced a small, reversible, multi-purpose connector years ago, while USB C is only just coming out, and getting emergency protocol patches to prevent the onslaught of cheap cables from killing more devices than they already have. A Google engineer is now warning people to stay away from some of the most recent devices using USB C because companies have already started to use the physical connector to go outside the boundaries of the protocol standard for it:
http://lifehacker.com/google-engineer-warns-against-phones-with-both-usb-c-an-1772442622
I currently have multiple Lightning adapters that cost me an arm and a leg that I would have preferred to keep...4 iPads ago. They have served me through each iPad switch, never had any issues with them, and in terms of cost per use they certainly are cheaper than pretty much any other thingamajig with a connector I have.
In the same amount of time I started having fewer and fewer devices with mini USB (still have some), more and more with micro USB. Just got my first ever USB C enabled accessory. With the single device I still have that uses USB B, that's 4 different standards I have now for USB cables alone (5 if you count the A end, 6 if you count the OTG-enabled adapters with more pins for microUSB, 7 if you do the same for miniUSB).
I have HDMI cables, but also mini HDMI and micro HDMI adapters, as well as a few MHL adapters. While I was using a Pebble I had two different magnetic charger cables, which obviously were different from the clip-on cable that came with my Sony smartwatch before that and the other Sony smartwatch I had before that again. Thankfully the MP3 player era is over, as the Samsung cable I had for one of those is easy to confuse with the proprietary Sandisk cable they used before they switched to mini USB (I never bought the new ones with microUSB). None of the three laptops I have use the same charger, which then leaves my Nintendo 2DS' charger as the final cable mess I have (not counting router and anything else with a smaller DC power supply).
Dual Lightning connectors allow the continued use of Lightning accessories. It also allows for more stability as it provides two connecting points to any larger accessories (such as the stand).
Ofc Lightning + USB C would be another option rather than 2x Lightning, but at the rate that the USB C community is both changing their minds and destandardizing their own standards, it's probably a good idea to put as few non-Apple connectors on things as possible.