English is a phonetically written language. It's not Chinese. If kids are taught phonics, they'll be able to learn and sound out new words for themselves. If they're only taught to recognize whole words by sight, they'll have a very limited vocabulary and be unable to pronounce unfamiliar words -- which is exactly what has happened to the generation that was taught the “look-and-say” (more accurately, “look-and-guess”) method of reading.
Fortunately, schools today are returning to traditional phonics -- after raising a generation of functional illiterates.