Where somebody's money moves is a better biography than where they say they live. Not the amounts, which are boring and private, but the choices: which processor, which currency on which leg, which route through which hub, and where the recurring debits actually land. Read as biography, the payment layer is one of the few surfaces a person cannot really groom without changing how their life works.
A person who tells you they live in one country and whose card use clusters in another is not necessarily lying. They might travel. But a person whose recurring direct debits, utilities, school fees, and small in-person retail all sit in a country they have publicly minimized for two years is telling you something about the gap between their story and their footprint.
Processors carry signal even without amounts; a person who pays through three different acquirers, each pinned to a different company, each company sitting in a different country, is operating a structure. The structure has reasons; some reasons are dull and operational. Some are not; determining which is the analytical task.
The most useful read from rails is not where money goes, it is where it does not. A wealthy person with no card footprint in their stated home market is unusual. A founder who pays themselves from one entity but settles personal bills through an unrelated trust account is unusual. A counterparty who insists on settling through one rail when their stated business needs three is unusual. None of these are conclusive; each warrants further inquiry.
Amounts are the market's domain; they have access private work does not. The relevant read is the shape of the activity, which is usually enough to indicate where additional scrutiny is warranted.