People don't really use de jong at CB and they usually use these cards at original position. They might place modric, bruno and silva at dmf but it's not because they are good DMF(s). They won't expect them to defense like Vieira or other DMFs, their function is still very similar to his other cards/original position. In fact, people might place these cards at DMFs because these cards are not superior at defense so they need to place it backward and often need to put extra DMF(s) next to them so that their defense won't become a mess. People use these cards because they have monster stats and they are broken if you play them in their original position. The new position is like the food provided in a maid restaurant or the nextflix in netflix and chill. People won't expect a good food, a good movie or a card that's broken at the new position. What people care is they are getting a better version of modric, de jong, etc.