The new capacitive wheel allows Audi to not have to use the torque sense method of hand on wheel detection, which is not particularly good. Then again, the capacitive wheel won't be much good either if it doesn't monitor all 360 degrees of the wheel.
Active lane assist and such things have been around since the 2015 Q7 (4M) release, but used that torque sense method. And that's been used until the capacitive wheel with the e-tron in 2018. In 2020, Audi rolled the functionality out to the rest of the lineup, though not sure about the TT. The A3 seems to have it starting with the type GY release. But the recent TSB about hands on detection problems (2061932/2) does not refer to the A3. Probably because we don't have the type GY A3 in the US yet (I assume).
So heated and flat bottom got dropped for vehicles equipped with such driver assistance functionality like active lane assist and traffic jam assist. Because heated is not compatible (yet?) and the only wheel they have is round (recently amended only for the RS6/RS7 so far).