i mean there are features that the apps have to enhance the experience. especially this patch is the one that enables Nvidia RTX HDR for multi monitor setups (which gives a better HDR experiemce than Windows implementation of it).
if you only need a driver, sure you dont need the app, but just because you dont use all the features doesnt mean its completely bloatware/no real advantage. (and Im saying this from the POV that geforce experience was overly bloated).
its functionality put into the app. its a feature not a part of the control panel nor gfe and only the new app. it requires the app because its also not a binary function. it gives the user a sliding scale to adjust the debanding intensity of HDR, as its Nvidias own implementation of what is essentially auto HDR.