Touch ID on iMac's Magic Keyboard won't work with iPad Pro
The Touch ID sensor on the iMac's new Magic Keyboard reportedly won't work with the latest iPad Pro, despite running the same M1 chip powering compatible Macs.

The Magic Keyboard bundled with the 24-inch iMac won't employ Touch ID on the M1 iPad Pro
Users can type on the keyboard while it's paired with the iPad Pro or other compatible Bluetooth devices. However, the keyboard's Touch ID sensor won't work with Apple's new tablet, according to MacRumors.
The updated Magic Keyboard ships in the box with the new 24-inch iMac that Apple announced in its "Spring Loaded" event on Tuesday. The keyboard marks Touch ID's first arrival on desktop Macs.
The iPad Pro already includes Apple's Face ID biometric system, which is faster and more secure than Touch ID.
While the keyboard's Touch ID support would have been redundant on the iPad Pro, the new tablet's M1 chip also powers other M1 Macs that will work with the keyboard's Touch ID. That broader compatibility had led some to speculate whether the two may work in tandem. However, Apple apparently saw no need to include external Touch ID support in iPadOS.
Apple bundles the new Magic Keyboard with more expensive models of the 24-inch iMac. The iPhone maker doesn't yet sell the keyboard as a standalone accessory, despite its working with M1 models of the MacBook Pro, MacBook Air, and Mac mini.

The Magic Keyboard bundled with the 24-inch iMac won't employ Touch ID on the M1 iPad Pro
Users can type on the keyboard while it's paired with the iPad Pro or other compatible Bluetooth devices. However, the keyboard's Touch ID sensor won't work with Apple's new tablet, according to MacRumors.
The updated Magic Keyboard ships in the box with the new 24-inch iMac that Apple announced in its "Spring Loaded" event on Tuesday. The keyboard marks Touch ID's first arrival on desktop Macs.
The iPad Pro already includes Apple's Face ID biometric system, which is faster and more secure than Touch ID.
While the keyboard's Touch ID support would have been redundant on the iPad Pro, the new tablet's M1 chip also powers other M1 Macs that will work with the keyboard's Touch ID. That broader compatibility had led some to speculate whether the two may work in tandem. However, Apple apparently saw no need to include external Touch ID support in iPadOS.
Apple bundles the new Magic Keyboard with more expensive models of the 24-inch iMac. The iPhone maker doesn't yet sell the keyboard as a standalone accessory, despite its working with M1 models of the MacBook Pro, MacBook Air, and Mac mini.
Comments
The Touch ID is there, sitting there useless like a tit on a bull.
What it is, is a lack of coordination across Apple departments, something quite unApple. That said, could it not simply be a software or firmware update?
It doesn't matter if some consider it a "downgrade." What matters is what the consumer wants. Personally, having 2 unlock options is an UPGRADE, even if one contends that one of those methods is less secure.