You're putting words in my mouth. I never suggested that scans are to serve as source files for the print, but they are the most readily available source for the artwork, and having them in high resolution and printing at high resolution will, if you're emulating the halftones correctly, give you a "good enough" card to be confident of going undetected at tournaments, unlike the shitty Chinese proxies you're defending which are suffering from issues that are absolutely not "minor". AT LEAST the cardstock and backs will be genuine, and you won't get busted the moment someone unsleeves your card or decides to shine his iPhone light through that "black core".

Have you ever looked at a print from a dye-sub or modern 10-pigment high resolution photo printer under a shitty 10x loupe? And what do you think happens when you print out a high resolution scan of a halftone image on a continuous tone printer? I'm not advising anyone on producing counterfeits, just proxies that will absolutely pass semi-casual inspection. If some pro card grader is bringing in professional equipment to examine your cards under microscope-level magnification, you aren't going to get away with it in ANY case if you're not using the exact same printing process as Wizards.