IMHO this is a classic example of extreme overcomplexity leading to fragility and regulatory capture along with increased opportunities for antiuser hostility. Practically all devices needed nothing more than +/- on a robust barrel jack, but now we have negotiable voltage (with disasterous consequences if there is a bug in the inherently software-driven process --- which will certainly happen) pushing insane amounts of current through a tiny effete connector with barely-visible pins, "authentication" schemes to enforce vendor lock-in under the guise of protection, and entire regions legally mandating this flustercuck.
Can I offer a counterpoint? Much like OG USB put a 5V supply within everyone's reach, USB-PD has made programmable, higher power supplies available to everyone. That's a big deal, because PSUs are an expensive portion of a product, especially for small manufacturers and hobbyists. Having a dedicated standard that supports multiple voltages and currents allows small players to take advantage of the same economies of scale as the largest electronics manufacturers.
Case in point, IKEA will happily sell you a very well built 20W power supply that provides 5, 9, 12, or 15V for less than $5 here in Canada, and you can get a similar price from legitimate Asian distributors, even when buying in limited quantities. If you're working on a small-batch electronic product, that's a boon to your BOM; if you had to go out and source a dedicated barrel-jack PSU with the same capabilities, it'd cost much more, and you don't know what kind of quality you'd be getting.
Where the standard really falls on its face, IMO, is in its opacity. You can get a chip that does the PD negotiation for pennies, but there is no way to inspect the protocol without shelling out thousands for a dedicated analyzer, so when things don't work, it's really hard to troubleshoot the reason.
(Disclaimer: I'm working on an open-source protocol analyzer, so this probably colours my view on the matter a little.)
This is purely a standards problem. The working group had to say "you don't get the logo unless you do PD" and have logo. They waited a DECADE to do that, which missed the boat, and when they did it they focused on transfer speed and wattage markings instead of a single stamp.
Is it? DC barrel plugs look identical to most users. Just like USB C. Only one of them negotiates the correct voltage by default in most cases.
This is a non issue, IMO. Does it depend on the electronics being designed correctly? Sure, but that’s the case for all electronics, and most devices probably build on some widely-available standardized control boards from 3rd parties.
As a user, I’m sooo happy that I can bring a portable battery and a wall charger, and both can recharge every single one of my portable devices. From gaming handhelds to large, powerful laptops, to wireless earbuds, to cameras, to smart watches, to flashlights. All with very different power requirements.
