It is frustrating. From a consumer's POV, the system just denies you stuff for no apparent reason. From a bank's POV, they're losing billions of dollars to car

It is frustrating. From a consumer's POV, the system just denies you stuff for no apparent reason. From a bank's POV, they're losing billions of dollars to card fraud operations, and there are very clever fraudsters who do their best to be indistinguishable from legit users. Legit users in rare situations (such as being cross-border) are often collateral damage. You can only understand what heuristic you're triggering by knowing a bit about patterns of fraud, which is an unreasonable demand on innocent consumers.