For what it is worth, I spoke to a CRA officer on the phone last week and she said that all I have to do is use "MY Account" to input the raw data in Auto-Fill and and the CRA will prepare my tax return.
I prefer a purchased software (like TurboTax) that is one notch or so below more expensive and exclusively professional software (like Cantax or TaxPrep).
Do you mean that you have to use Auto-fill in conjunction with a real tax prep software like Studiotax? In that case, I might as well just go with Studiotax and avoid involving Auto-fill.