Here's another bit - USB C is expensive to make cables for! There are a lot of small pitch pins, and you certainly can't stick a 'usb c' logo on a charge only cable. A simple cable also stops any sort of USB-C benefits. Search for some interesting bits from gamersnexus youtube about computer case manufacturers on why there's not more USB-C on cases.- mainly that they're complex and manual (still!) to wire up. Secondly, I'm not honestly sure if usb C supplies will even supply 5v 1A without negotiation (requiring logic, requiring more wires in the cable, requiring USB-IF), unlike a USB-A DCP charger which most just pump out 5v regardless. Got to consider on the barrel jack front that it's also protection that only that charger should be used -- maybe you could label 'use only supplied charger' but use USB, but by the time you're trying to certify with USB that's itself nonstandard (just two wire), headaches ensue. Wheras ironically due to too many standards (Apple 1.2A, 2.4A, samsung 1.2A, DCP...) anything that charges at 5v using USB will probably just work with any charger, since internally they default to pumping out 5v up to whatever current limit....and most dumb devices will use well less than that current limit. Plus many android smartphones will probably also just work with any charger, despite all the many standards by just trying higher and higher currents until the supply starts to droop. MicroUSB cables that are 'charge only' are about as cheap as it gets, just two conductors. But any device that works with such a shoddy cable will also work perfectly with ANY better (4 conductor) cable. Can't do that with USB-C. Barrel jacks are useful particularly for home appliances where the power supply is meant to be specific.