Here's an interesting
article on US-C and some problems. No design is perfect. Anecdotally, I had a USB C connector fail rendering a $70 hub useless (and 1 year and a few days out of warranty, thanks Kingston). Does that mean USB-C is bad? No, just as with any connector tehre are tradeoffs and weak points.
Some key points for the TL;DR crowd:
The pin pitch of USB‑C connectors is 0.5 mm ― much tighter than the 2.5-mm pin pitch in USB Type-A connectors. This tighter pitch significantly increases the risk of a fault that could cause a thermal event. When connector pins become deformed or dust, metal particles, hair, or other debris gets stuck in a USB‑C cable connector, a resistive fault can be created from the power line to ground. These resistive faults can cause a dangerous temperature rise while increasing current only minimally. Damage to both cables and devices, even fire, has been reported (Fig. 1 ).
One interesting thing in the article is the discussion of designing cables to withstand 60 or 100W PD and deliver the advantages of faster charging:
As important as these advantages are to users, it’s equally important for designers to consider the safety issues associated with power and temperature management at the cable-to-device connection. Without proper circuit design, including temperature monitoring, cables and connectors can accumulate contaminants inside the connection, causing them to heat up quickly, which can easily damage or destroy the cable and the mobile device.
It talks about the how to adress temperature protection to protect the cable from over temperature failure. They involve insererting special devices in teh cable, which of course cost money. One danger is cheap cables may forgo these protections and as a result may experience thermal failure. The selling point is one cable to rule them all but unless every cable is made to teh highest specification end users may experience failures and wonder why, since "it was a USB-C cable..."
Is this a reason not to go to USB-C, no, nor does it mean Lightening is a worse choice, just different and situation specific. It highlights the challenges in educationg consumers and properly marketting cables. I doubt the Chinese factories churning out cheap cables will bother to ensure tehy meet thermal protection requirements for the capacity they can carry.
The Eu will need to mandate testing and labeling if they want to protect the consumer.