Why? USBC is ubiquitous for everything except iPhones by this point, even in Apple's lineup. All macs have been USBC for 7 years now, most of the past decade, all the iPads are now USBC. For folks that pair their gear with beats those are USBC too.
The plug for the standard apple watch charger is now USBC. Even the most recent lightning cables use USBC on the plug side, so chargers have all moved over to USBC. Consistent cables and chargers across Apple's products, and the ability to share cables and chargers with your android fam and friends, is huge.
It's even more huge in Europe, India, Brazil, or other countries considering similar regs than the US because iPhones are not as a big in any of those places as they are in the US. In the US iPhones are the majority of phones at just over 50%. In Europe that number is ~30%. In Brazil it's 15%. In India it's a whopping 4%. Lining iPhones up with the majority of other users is a huge boon. It also just makes life much easier, especially if you're using the general apple ecosystem. Being able to just plug into any cable in my house with any of my Apple devices is a massive convenience.
For folks in families or etc that are mixed iPhone and android it helps too, no more keeping multiple cables plugged in in your car, by the couch, etc to make sure everyone can charge.
And if you think it's a "crap need to replace my cables with a new phone" problem, people already chew through cables anyway. They break, pets get to them, kids get to them, they get lost, etc. People buy new cables all the time, that's why Anker and co sell so many on Amazon to begin with, or every smaller brand, or amazon basics. That's why every gas station has a pile of cables at the counter. That's why every convenience store, bodega, pharmacy, grocery store, etc have them. That's why you see street vendors everywhere with cables. Etc. Now it'll be a more ubiquitous cable that everyone can use. Not to mention if you're buying a new expensive phone it's not like you can't buy a $3 cable to go with it.
And, as I said, the regulation is super popular, so stats say you're wrong anyway