No you *don't* get two of those things for free. You get a lightning to usb-c cable with the phone which doesn't charge charge other USB-C devices in the house such as a spouse's Android phone, a laptop, headphones, PS5/Xbox controllers, list goes on... Also an Apple watch charging cable will never give you a single cable charging experience which is one of the main reasons for getting the duo charger.
Keyword *if*.
Not everyone that bought an iPhone 12 bought an iPad with a USB-C port. Talk about drinking the juice, that's some classic cherry picking of info there.
1. A MagSafe can charge most modern Android phones and other accessories for one since it's Qi charging compatible. Lightning cable can't do that. Immediately you're wrong there.
2. People prefer wireless charging. What you're arguing is essentially "why do people want wireless charging" which is a completely separate argument as it has less to do with the duo charger. If you want wireless charging, MagSafe guarantees alignment which is the #1 problem with Qi chargers as many have started their day with 10% battery because of Qi chargers.