Lots of external hard disks/bank card magnetic strips will get wiped by the magnet in the iPhone 12.
The last thing techies want is a phone that has a powerful magnet in the back, because they're forever putting the phone down on a bench next to spinning hard disks, external storage drives, on top of rack mount devices or microservers. How many techies use their phones to take apart laptops/PCs etc, take telephoto shots of product numbers on integrated circuits?
Apple really should have just produced an iPhone case with a magnet, not the iPhone itself, or at least have a model of iPhone 12, that doesn't have the magnet in the back. How hard is it to plug in a lightning cable, I really don't get the obsession with slower wireless charging, not least because it's so wasteful in terms of transferring energy.
It's almost like Apple are going out of the way to destroy bank cards, so people switch to ApplePay and external storage drives, so they use to iCloud backup. There are going to be a lot of people, suddenly finding their WD/Seagate external storage drive has been wiped after leaving their new iPhone 12 on top of it.
Remember, don't carry your new iPhone 12 against the underside of an older laptop, don't set your iPhone down on an external storage device, microserver.
Outdoors, take care too, not to put in a rucksack with a conventional compass if out walking.