Earlier quoted context omitted.
Electronic Money Transfer (EMT)/e-transfering is a bank-to-bank transfer in Canada.
It may be convenient use other ids besides bank account numbers, but it adds another avenue for mistakes.
Such as...?
To me, passing around a long unstructured numeric string is a lot more error-prone than selecting a contact from my banking app, or writing a short, structured phone number or email address. In any case, the recipient needs to know the secret one-word answer to the question set by the sender, which would prevent wrong parties from claiming money (this can be skipped if the recipient registered their phone number or email address forbauto-deposit).