On the one hand, yeah, USB-C works great, and everything else I own takes it. On the other hand, Lightning also works great, USB-C isn't an improvement on the merits, and iPhone users have a bunch of accessories for it. Like in my car, I have a 12v charger with one USB-A port and a built-in Lightning cable, and I'd have to either junk it or just ignore the built in cable if they went USB-C.
I'm pretty sure the writing is on the wall with MagSafe: Apple intends to ditch the port entirely. That makes me nervous, frankly, and there are people out there who use an SD card reader who would be furious.
But I think that future is more likely than one in which Apple ditches the Lightning port for USB-C. We'll see.