Because its Apple... and they moved on from touch ID even though having both would be damn useful, but Apple only do things Apple wants not what people need it seems. The 13 series should have had touch ID on the power button I mean theres been a pandemic for a while now, but why give you a power button option when 'look here is an Apple watch' Call me cynical but thats how I see it. Get an Apple watch then you wont have to take your mask off, makes them more money than putting something sensible like a fingerprint reader on the phone.