Switching from VISA to MC may not work. If you read through the second article linked, you'll see that Warren wasn't the one who initially instigated this; it's been in the works for some time (I imagine Warren just wanted some press out of it for her flamin' leftist constituents).
What's more troubling, it's ISO, the International Organization for Standardization (as in ISO 9000, etc.) that maintains those financial codes as a worldwide standard. I have no idea if a credit card issuer or merchant bank can completely opt out of one or more particular codes, but my bet is that an individual institution may be able to choose which of the codes they use, but that the financial networks--e.g., VISA, MasterCard, AMEX, Discover--can't. Since ISO maintains it, it's an auditable standard. The networks probably can't pick and choose because that would mean there wouldn't be a global set of codes: they couldn't exclude codes from the international standard because that would prevent them from processing some transactions...or at the least prevent them from being able to pass the expected coding data back and forth around the world.
Edited to add: Found the actual ISO standard, but the ISO page for it doesn't tell us much, other than that new modification hasn't been published yet: https://www.iso.org/standard/33365.html.
Here's a site with more info: https://classification.codes/classifica ... ustry/mcc/. It explains a little better how the Merchant Classification Codes are used (note the last bullet point):
MCC codes are assigned by the acquirer to merchants using their services according to the guidelines published by the payment card organization they work with. An acquirer (acquiring bank) is a bank (or a financial institution) that processes debit/credit card payment on behalf of the merchant. For example, when a bookstore starts doing business with MasterCard it will be given MCC code 5192. These codes are then used:
- to determine the interchange fee paid by the issuer (a bank or a financial institution that issued a card) to the acquirer
- categorizing transactions of the credit card statement
- to prevent certain types of purchases on some cards (e.g. corporate credit cards may prevent purchases at some types of merchants)
- in risk assessment of a credit card transactions
- in credit card reward programs, where the credit card user gets different rewards for spending on certain categories of items
- (United States only) in payment reporting to IRS under section 6041 or section 6041A of the Internal Revenue Code (Form 1099-MISC).