Why do watches with roman numerals have a "4" with "IIII" insted of "IV" which is the correct way?

Early on, IIII was correct. In later times, this gave way to IV. IV is simpler, and became preferred. Although IV is currently considered by many to be more correct, this is not true. Both are correct. One is a more recent development, and therefore is typically the prefered, and simpler, method. However, who can seriously state that IIII is incorrect? When confronted by such people, laugh at them. I recommend using IV for the very reasons that it was developed, but not because it is somehow "correct".