I myself still see "m a r t"--at least in the image the way I originally posted it. (It is possible to get too close and have too much contrast or too little.) Other letters don't even occur to me until people point them out, and even then they seem strained.
Why would these letters be on the card? Well, I think the letters are there because the designer of the deck wanted to say that the CY was a deck with good Christian images, not idols like Marziano had. He is lumping Marziano in with King Ninus in order to sell his not very original product to Marziano's critics. He has taken Marziano's game, which people either knew or could read about, and tried to make it more acceptable. In other words--I might as well say it--I think the game that was later called "tarot" was originally invented by a Christian humanist who thought there was wisdom to be gained from pagan mythology, both the "good guys" (virtues, virginities) and "bad guys" (riches, pleasures) among the Greek gods. The CY is a Christianization of that game, a response to criticism of its idolatry, and its designer wanted to distance himself from its originator. At the same time, I suspect that it is probably inappropriate to say that there was any one inventor of tarot, just as there was not any one inventor of the automobile (whatever Obama says, Frenchmen invented an impractical steam version, Germans gave it a decent engine, and Americans just made it a consumer item).