Aadhar is meant to be private but it cannot be used for anything without MFA (unlike SSN). In that sense, Aadhar is not really treated as a password like SSN is.
Aadhar is not meant to be private. It should not be treated a s a private key when you need to give a copy of your card everywhere like your bank, getting a new cell phone sim card, employment, etc. The problem with Aadhar (among other things) is that people think its a secret. Its not supposed to be that way.
SSN is meant to be a secret but it's required at all the places you mentioned. At least with Aadhaar, if someone got a copy of my number, it can't be used without MFA.
What kind of private it is when DHL holds your international incoming document parcel hostage asking for Aadhar copy for Customs Clearance; then delivery boy insisting on Aadhar photo in his phone for making sure to deliver to right person.
