> I remember living in Belgium this was the case, and I always had to go and find that stupid physical barcode reader that I then had to hold against the screen, sign in with my debit card, PIN, enter the Euro amount, and then sign the transaction.

I can't talk about Belgium but from what I've read, the dutch iDeal system requires nothing of the sort. It seems to act as a broker between your bank and the business, and a user's input is limited to pick the bank you use and approve the payment through your bank's app.

It used to be the case in the Netherlands with iDeal that you'd use your bank's e.dentifier for two factor auth (a physical device that you'd put your card into to get a code you could then put into the website to verify) - they replaced this with using your banking app sometime over the past 10 years.

When using the web interface some banks still offer the physical reader (which I prefer), but the banks are pushing hard to move to the phone app.