For people who already have USB-C phones and are considering switching it means "All of the cords you have right now will still be useful", which is a definite improvement over "All of the cords you have right now are junk you will throw away and have to replace with new cords".

I'm not trying to say that will drive massive upgrades in and of itself, but I can definitely see it being a nice-to-have at the margins and help a nontrivial set of people pull the trigger.