I think that's precisely the problem - chargers come in all variations, and not all meet the charging requirements of Apple products. I see this as an answer to people who either don't want to have to deal with the hassle of figuring out which third party chargers work properly with their apple devices. It's like Apple releasing the 20w charger to replace their previous 18w charger because the latter wouldn't work properly with their MagSafe chargers.
What's more interesting isn't the charger itself, but the why. Why two ports, and why 35w specifically. Does Apple have a particular charging setup in mind for users? Who is this for?
Nothing Apple does is ever random. You think people would have figured that out by now.