The treatment may be location specific. I had my oath ceremony yesterday and at the end checked with the officer whether I could get an e-certificate. I was not asked for any justification (I had already said I had no immediate travel plans) and she said it's doable and that I would not get a paper certificate. The only thing I was asked to do differently was to add in the body of the email with my oath form that I had requested the e-certificate during the interview.Got an answer to my question about getting an e-certificate:
The electronic certificates (e-certificates) are available upon urgent request. It is necessary to ask for it at your identification for the ceremony. Once the file is closed, it is no longer possible the change the format.
This morning I received email instructions to access the certificate and was able to download it.
My office is Mississauga.