Why did the ancient Chinese create such a beautiful but difficult writing system?
Chinese writing evolved. It started out as pictures. Sometimes they used images to represent ideas; even in today’s writing, you can see that 大 is someone standing with their legs and arms spread apart, thiiiis big! Sometimes you have to know how to look at them. For example, 車 (che), originally chariot, the | is the axle, the two short lines at top and bottom are the wheels viewed from above, and the 田 in the middle is the body of the chariot. That stands for the whole chariot.
Chariots were used for war, so if you put a ㄅ (人, person) on the 車, you get 軍 (jün) army. Then if you add 辶 movement, you get 運 (yün4) transportation. So you can see that the characters developed as society needed them.
Modern simplified characters have done away with much of the internal logic of the characters, form and sound, but the traditional characters retain the system. If you understand it, it is quite logical and may seem difficult, but isn’t nearly as difficult as English spelling.