I notice there are two levels of security on my banking apps. I am unable to set up new payees using the app on my mobile phone, although I can pay anyone from a dropdown list of payees that I've already set up.
However, I can't create a new payee from my phone app, I have to set that up using a card reader having logged on to a desktop site with the stricter security measures. I also get a text message to say a new payee has been set up.
There are also payment amount restrictions using mobile phone apps that are not on desktop sites.
I'm not sure about limits on contactless payments using a mobile phone. I haven't checked that although I've started using it. It's not much different from using a contactless debit card, without the paper receipts.
The other benefit of mobile phone banking apps is that you can see your account totals and transactions at any time. A quick check can provide reassurance and it is also simple to block your card if you think it has been compromised.