What would you consider as key performance indicators (KPIs) for a mobile marketing strategy?

I've chose DAU (Daily Active Users) and CPI vs LTV (Cos Per Install compared to LifeTime Value), would this be suitable for a mobile app of a bank?

A bit of a reasoning behind "There is no point in acquiring users if they don't come back on a regular basis to use our app or service. And since we want to create a positive ROI (return of Investment) we will focus on acquiring users through our CommBank App or the website, luring customers with the idea of the simplistic mobile banking."

Just wanted to check, if this is a good approach. Thank you!