> That's never going to be practical for a person who lives in Vatican City. If he's going to be living in the Vatican until he dies he might as well use a local bank.

These may have been 'legacy' accounts, as he was a bishop in Peru for almost a decade:

* https://en.wikipedia.org/wiki/Pope_Leo_XIV#Bishop_of_Chiclay...

So he was born and raised, and had early ministries in the area, but has been outside of Chicago for a number of recent years. It may have been easy enough for him to travel back home (?) when he was 'only' a bishop or cardinal, but has been more difficult more recently.

Dealing with / consolidating old accounts may not have been a priority for him.