I believe this is because the tracking dots[1] require yellow ink.

[1] https://w2.eff.org/Privacy/printers/index.php

Well, why can I print with just black ink on my canon and HP multifunction printers then?

(they also allow me to do high-res (4800dpi) scans of money without any issue, in hilarious contrast to photoshop, which refuses to open them)

Maybe you got to have them inserted, yes, but they can be empty. (My HP OfficeJet 6500A Plus also prints with empty color cartridges. I just replaced them today after weeks of emptyness).

this is not unique to epson. hp and xerox printers do the same thing.

I had Lexmark before, it was never a problem! unbelievable, the thing is that I never used the colors, they dried out! You have to buy all of them just to print in black!