Why do people think it is a good thing to have this enforced by law is beyond me. I don't see any win besides a minor convenience. A lightning cable weighs almost nothing and it's not a big deal to have one around. As to lightning port limitations, I question whether usb-c will give average iPhone users any other advantage other than charging their phone. What are people gonna do with it other than charge their phone…
A LOT of less waste maybe ? It is very inconvenient and a hassle to have 5 different cables for 5 different devices. It is a waste of space, materials... The economic gains by volume continent wide should not be underestimated.
Cables (generally) don't go bad in a year or two and can last for quite a few years. Most long-term iPhone users probably have at least a few spare cables throughout their desk, house, car that they've bought over time that they'd now have no substitutes for and would need to replace.
You might have dictated a situation where people now have to throw away a pile of perfectly usable cables/accessories and buy a bunch of new ones. While well intentioned, this law might have otherwise achieved the opposite of what it set out to do.
PS: Whether this law exists or not, I'd have bet on Apple working to go fully wireless soon and this might just accelerate that effort.