In addition to some of the other very valid points above, your comparisson seems to be focused solely on electricity usage and only considers the 2 Visa data centers in that evaluation and ignores the millions of always-on POS equipment required to actually transmit data to those centers.
Furthermore, in that same article you linked, it is estimated that *one* of these data centers costs "hundreds of millions of dollars" to build, and at 8 acres in size, I'm sure it's staffed by many employess, who probably demand some kind of salary for working there.
Then when you consider that all of this is just to provide Visa services, which is only one aspect of the financial system, you can *maybe* start to see how you are comparing apples to dwarf stars.