Ask HN: In an app-centric world, how does one protect themselves from fraud?

There's been a number of stories recently in the UK about phone thieves draining peoples' current accounts and savings. Phone theft is a major problem in London.

  "Mobile phone fraud: 'They stole £22,500 using my banking app'": https://www.bbc.co.uk/news/business-64240140
  "Fraud: 'I had £18,000 stolen after my drink was spiked'": https://www.bbc.co.uk/news/business-59494524

From what it sounds like, these unfortunate people had the same security measures on their phones as everyone else.

This prompted me to review the apps I have on my phone especially the ones I use for savings. I mainly use Zopa, which doesn't even offer a web dashboard. It's app only.

In this case, what are cautious people supposed to do? Have a second phone that stays at home? We are lucky to have very modern and accessible financial services in the UK, but sometimes it feels too modern.