Depends on the bank's policies. Currently it tends to be when you transfer to a new destination and/or above a certain amount. I could certainly imagine a bank requiring it for every PC-initiated transaction as and when they reach a point where most normie customers are using their app.
> What type are transactions are you talking about?
Bank transfers and I guess direct debit authorisations (if your bank requires you to confirm those) and reauthorisation/confirmation of card payments that were blocked by the bank's fraud detection. I think those are the only kinds of transactions one would ever use a PC for? I mean for me most of my day-to-day transactions are me paying by debit card in a shop, but you can't do that on a PC in the first place; pretty much everything else I do on my PC.
No. Only to unblock when they get blocked/flagged as fraud (tends to happen for large transactions like plane tickets or buying a bunch of furniture), and even then I currently have the option of authorizing via the web browser (and I think also via phone call).
But sending a bank transfer is also a fairly common day-to-day transaction that I do a couple of times a month (and is the only way to pay for some government services like tax certificates short of visiting the tax office in person). Authorising a new direct debit happens occasionally (joined a gym, changed my utility provider, got a new credit card, that kind of thing).
My brokerages require it every time I login from a computer. My bank will require it if it can't find a cookie from a previous login session. Occasionally, my bank will require it seemingly randomly since I usually log in at least once a week from my laptop yet every couple of months or so I have to reconfirm on the app or another secondary method.
AFAIK Zelle is something US banks got together and set up on their own because the government didn't. So a Zelle transfer is the US equivalent of a SEPA transfer.
