It's not instant and it relies on a private company for settlement. Even though customers typically get this for "free", the institutions themselves are paying interac for these (so the account-holders are paying for this one way or another)

From what I can tell, e-transfers will continue using interac's network, so I'm not sure if this will benefit users at all. Depends if banks integrate a new user-facing money transfer option. I suspect it'll take years if not decades for banking institutions to roll this out to users, though they may use this behind the scenes for inter-institutional transfers without Interac.

Someone who's more knowledgeable about Canadian banking and payment processing, feel free to jump in here because I'd like to know more as well.