OK, I'll be direct: "Because it's a really bad idea."
But if you think it worthy to try, try it. Gain experience with how it works out.
Why is it a bad idea?
When you pass Pearl you have Manila and the submarines left, they also are no sure thing if your hit goes badly.
What are you giving up?
You are giving up damaging/destroying anything with KB on turn 1. Unless your mod or rules say turn it off, Japan has surprise on turn 1. It helps a great deal for attacks that day.
My priority target after carriers are long range search capable planes, you can get some in the Philippines with LBA.
In my experience long range search planes are destroyed in greatest numbers at Pearl Harbor on turn 1.
Hiding KB will make the allies hesitant to act anywhere or with good luck even getting a shot at the carriers.
It is a pretty standard rule "no carrier hunting on turn 1" because the Japan player knows exactly where they start, something which was not true in real life. Some PBM partners extend that to turns 2 or 3, but IMO turn 1 is appropriate. So if you do have such a rule (no carrier hunting on turn 1), do you plan to search for the carriers, or do you plan to hide KB to keep the Allied player guessing? You are saying both and those options conflict with each other.
The Allies don't NEED to use their carriers early, they can wait for more to arrive to strengthen the fleet. If you get the Allied carriers good for you, but if you don't then you have held back your most potent offensive weapon for nothing. You have denied use of it to your various expansion operations.