That means that the only way to use biometric authentication with an iPad Pro is with Face ID.
It should be noted that this keyboard only comes with the new iMacs if you pay $50 to upgrade it, and it’s currently not sold on its own. So unless you were planning on buying a new iMac and a new iPad Pro, this doesn’t really affect you. If you do fall in this minority, you can use the new keyboard with the iPad Pro, just not the fingerprint scanner.
The keyboard does work with other M1 Macs, including the Mac mini, the MacBook Air and the MacBook Pro.
I suspect that at some point, Apple may start selling these new Touch ID enabled keyboards separately, but it likely won’t be until the M1 Macs take up a larger portion of the companies sales.