Same reason why, at most UK banks, your online credentials (both user and pwd) are case insensitive: it's convenient to the customer. It costs less money to "pay" for the reduced security than it does in attrition causing customer dissatisfaction (which makes them leave), missed transactions, customer support hotline ("I can't login"), etc,

But it is so secure in the movies!

It is incredibly convenient. You never take the headset from your ear. Time is money, and those fractions of an cent…

It also sounds (no pun intended) high tech. Which sounds secure. Which is often more important than reality.

The main Australian government department which handles things like Medicare, social security ("welfare"), etc has the option to use voice recognition, and they promote it.

eg printed flyers selling people on the idea, etc.

https://www.servicesaustralia.gov.au/create-your-voiceprint

https://www.itnews.com.au/news/services-australias-voice-bio...

Possibly even worse, the Australian Taxation Office (ATO) - our version of the IRS - has been creating voice prints of all callers for the same purpose.

https://www.ato.gov.au/General/Online-services/Voice-authent...

And they reportedly ignore caller instructions to opt out. :(

A broader question would be about biometrics in general. It was not too long ago when these were widely promoted, but now with advances in AI these seem to be increasingly an attack vector.

I wonder if you can opt-out of that? You're right that it seems insanely unsafe, my bank have been legally forced to use two factor authentication for more than 10 years.

I've experienced a bank more or less forcing me into accepting it

Because for low-stakes authentication like "pulling up your account" for the customer service worker it's fine.