why don’t think about a bonus system?
For example users which are bringing you a lot of “good” transactions or have high balances should be allowed to withdraw more cash for free per month at ATMs.
Or another fair idea would be to move unused free ATM withdrawals to the next months.
Also getting “Revolut points” for spending a lot would be a nice feature. That points should later be used to lower fees or transfer into real money or getting goodies. There are so many possibilities to bring users to use their cards more and bring you more income - so that would be nice for both sides