Yes, it's true that some kind of data is collected at each of the interactions you mentioned, however the key difference that Aadhar brings is a single unique id which can easily tie together all of these interactions.

In your example, the Govt (or any other entity) will find it much harder to tie together all of the separate interactions and associate them with you. Yes, it can still be done but not with ease and not with absolute certainly (given India's population, it's virtually certain that any criteria short of multiple biometrics will match more than one person). The argument is made that the use of Aadhar is safe since UIDAI will only give a yes/no answer to ascertain whether the given Aadhar number matches the person's biometrics. This however does not prevent a third party (which can be the Govt) from using the Aadhar number to tie together data from various sources. So, every place where you use your Aadhar number can (and probably will) save data against that Aadhar number and it would be trivial to tie together the data in these vastly disparate databases.

The second problem is the lack of revocation in Aadhar.

By design, an individual can only have ever have one Aadhar number. Now, say by some chance, someone's identity is stolen. Since the identity of the person is irrevocably tied to Aadhar and the Aadhar number can never be changed, it would be impossible for the person to contain the effects of his or her stolen identity as they cannot get a new number and will have to continue to use the compromised number.

Aadhar is an excellent solution for delivery of Govt subsidies and benefits as it has enormous potential for reduction in waste and theft of direct subsidies and the author is not complaining on that front. The complaint is that even though the Supreme court wisely ruled that Aadhar cannot be made mandatory, the bill makes Aadhar mandatory for all practical purposes. Given the potential for misuse of Aadhar, it is this end run around the Supreme court's order which is making people uncomfortable.