In Canada, bank transfers are so seamless that I see no chance of this ever gaining traction. It's called Interac e-Transfer, and all domestic banks are part of it. All you need is access to online banking, so it's universally available. It's free, too (for personal accounts).

The way it works is the sender signs into their online banking and initiates an e-transfer. The sender doesn't need the recipient's banking details, only a phone number or email address. The recipient follows the link in the email/SMS message they received, signs into their online banking, and selects the account to deposit the funds into. The entire process is immediate.

If the recipient has registered that email address or phone number to auto-deposit into a specific account, all the sender has to do is type in the amount and hit Send. Otherwise, they will have to create a short question with a secret one-word answer that the recipient needs to answer correctly.

How could WhatsApp payments be better than that? Not everyone has WhatsApp, and if you want to use it you'll need to go through the hassle of linking your bank account.