The idea is to show the amount spent today (and for any other day, per day) as you would see the number of steps today in Apple Health app.
This feature would allow users to better manage money by seeing how much they spend today vs other days. The app could show averages and trends to alert users about their spending going up or signal to users when it is going down. There could be a section for users to set their daily spending goal and keeping track of it, e.g. $20 out of $100 daily budget spent today. You can add ability to trigger alerts after daily budget is exceeded or when users are about to reach it, and an option to auto block payments after the daily budget is hit if users want to limit their spending.
With our phones being with us all day, it is easy to overspend and in most cases one just can’t just leave the phone at home.
Real-life example of the feature: Revolut.