Why because they planned to use them in a future weapons program.
If the regime were planning on using it, they would have stored it in a bunker or some other secure place, not a hole in the ground.
The scientist probably burried it thinking the first war wouldn't last long and he could dig it up in a few weeks, when Iraq lost and was disarmed, there was no reason to bother.
You don't burry sensitive and sophisticated electronics in a dirt hole in the ground as a means of long term storage, the probability of this stuff being servicable is less than zero.
would you bury your washing machine or television in the back yard?