Apple hasn’t secretly wiped away TouchID. In common with all models of iPad Pro released in recent years, your iPad Pro model uses FaceID, not TouchID - whereas other models of iPad use TouchID.
All models of iPad in recent years support either TouchID or FaceID - but not both.
All iPad models that support TouchID have a physical Home Button at bottom centre of the screen - within which is the TouchID sensor - or for iPad Air4, mini6 and iPad10 incorporate the TouchID sensor within the Top (Sleep/Wake) button.
iPad models supporting FaceID, such as your iPad Pro, have a FaceID sensor (consisting of an Infrared Dot Projector and TrueDepth Camera array) - this sensor being absent from iPad models that support TouchID.
FaceID is offers both higher security and stronger authentication than TouchID - with a significantly lower false positive authentication rate. Fingerprints can be easily damaged, leading to a higher rejection rate for the bona-fide owner. In some environments, in particular those with low humidity, or for users with very dry skin, TouchID may not work at all. FaceID removes the physical limitations of an electro-optical touch sensor, instead using a sophisticated 3D optical system to authenticate the user.
In addition to authentication, the FaceID camera system also provides attention-aware capabilities and functions that simply cannot be implemented using TouchID. The attention-aware features are unobtrusive - and, for most part, you may not even be aware that they are there until such time as you switch-back to using a device that doesn’t have these capabilities.
