Fingerprint for every transaction

Would it be possible to implement finger print authorisation for all transactions online ?
I’m guessing it wouldn’t work with Paypal ?

If they use securecode I think that already happens if it’s configured in the app.

if they don’t, it’s difficult to see how it could be enforced.

Are we not far off scanning the iris? I appreciate this might seem a little flippant however think back to 2004 - no iPhones.
I do like the Monzo version of secure code where you don’t have to remember your secure code but go in app and authorise.