Not a problem for an enthusiast like me that visits sites like this daily. For my own personal usage, I welcome the usb-c cord being standard - it's what I want for all of my devices.
But for so many others that haven't bought a new gadget in a while, meaning this will be their first usb-c cord for a device, they won't even see this coming. My sister plans to upgrade her iPhone 8 this year, and I can think of two others in my social circle who are waiting for the next iPhone. I can say with absolute certainty that they don't have a usb-c power adapter. They'd be in for quite the annoyance if I'm not around to give them a heads up.
And I'll also have to let them know that they don't have to throw away their USB-A cords and adapters. That they'll still work, just not as fast. That's going to be a lot of trash/waste for those that assume they're completely obsolete.
EDIT: Oh, just realized my thoughts are flawed. If they already have other USB-A adapters and cords, this isn't much of an inconvenience. More of an introduction to usb-c as an option.