The reason the developers put in a clock is to change the time if you moved timezones or it was daylight savings. It's in the technical options menu for that reason.
The implied lesson in Animal Crossing after all is to relax and do casual things like catching bugs and fishing, not speed up time to do everything even faster. I feel like these forums constantly stress and preach how to play the game in your own way because people are afraid of offending one another. But in all honesty the game wasn't meant to be played with time-traveling. If it was, time-traveling would not have any consequences at all and the game would be advertised and defined completely differently. (Change your clock to make it Easter in September kids!)