To be clear, although this distinction won't matter to 99% of people, financial institutions need to COMPLY with laws and regulations, they do not need to proactively ENFORCE them.
The best example to demonstrate this would be a bank that has lent money to a customer in the form of a credit card. The customer one day goes to pay off their credit card statement balance, and they disclose to the bank teller that they're using criminally acquired/misappropriated funds to pay that debt. In that situation, enforcing the law would mean participation in apprehending that man to see him brought to justice. In reality, because they don't expressly enforce laws and instead comply, their responsibility in that circumstance is to follow all routine procedures in applying those funds to that outstanding debt. They can voluntarily additionally notify law enforcement, but it is not required.
There's some, but not many, cases where compliance and enforcement overlap, and when they do, it's almost always in the capacity of mandatorily reporting information to law enforcement, such as suspected money laundering or elder financial abuse. The suggestion that Mastercard or Visa, in order to comply with regulations, need to identify and demonetize obscene materials, is fanfiction. If they were required to enforce the law, then they'd have to demonetize Cloudflare for its role in maintaining access to bountiful amounts of illegal materials.
Yet, they don't, and instead strongarm digital video game storefronts and sex worker platforms like Fansly due to self-constructed standards. There is no law in the United States that prevents autistic faggots from dressing in fursuits to film themselves simulating bestiality for money from strangers on the Internet, as disgusting as that might be, and yet Fansly was forced to wholly blacklist that material.