Why does ALLAH SWT equate to the world with water ... ???

Why does ALLAH SWT equate to the world with water ... ???
Al-Imam Al-Qurthubi Ra stated
When ALLAH SWT said
AND GIVE THEM TO THEIR PEOPLE ... THIS WORLD LIFE IS WATER THAT WE ARE REDUCING FROM THE SKY ...
Said the scholars of wisdom
ALLAH SWT likes the world with water because

1. Water can not stay in one place
   So the world will never remain in one state.
2. Water will pass and will not remain
   So the world is mortal and impermanent
3. Someone will not be able to get into the water without getting wet
   So the world
   no one will be saved from slander and ugliness
   4.And ... water will be able to provide benefits, will be able to grow crops if appropriate size ...
   if too much pouring water
   it will turn off the plant
   So the world
   will benefit if used in moderation &
   will damage if exaggeration of it