There seems to be a few times in the iOS app (can’t speak for Andriod) where the standard keyboard is displayed, instead of the built-in iOS keyboard type that’s more appropriate for the data being entered:
Account Number & Sort Code should show number pad: (Starling vs Monzo app)
URLs should show the URL keyboard:
There is even a keyboard optimised for Twitter input:
I think this especially important for entry of account details as using the number pad isn’t just quicker and easier but also reduces the chance of typing a wrong digit, which can be especially disastrous!