This song has three chords - C, F, and G7 (I, IV, and V7). Giving the songwriters credit for all three, however, is misleading because the G7 chord is used once during this four-minute song. The harmony involved in this song is an example of why intellectual musicians make fun of popular music.
However, the lack of harmonic creativity creates a couple of effects that I felt. First of all, I actually heard the words, and paid some attention to them. Thinking about the last time I heard an opera or musical, I realize that perhaps there's some value to this. I may be simple-minded, but maybe the average person can't pay attention to words and complex music at the same time.
Second, I felt very content listening to the song. Whereas music with harmonic motion generally has some emotional impact on the listener (even though it may be subtle), this song was just calming - which may also have value in that I could listen to it repeatedly.