Why is it important that we have a written Torah that is written according to very specific rules with all copies being exactly the same?
One of the beautiful things about the Hebrew language is that each and every letter has a unique symbolism and meaning. They are not merely symbols for sounds, but have a deeper understanding as well. This is based on the particular letter form of the letter, and is expounded upon at length in many Kaballistic works.
For this reason it is imperative that each letter of the Torah be formed accurately and with great care so that the holiness and meaning of each letter is transmitted properly.
The Talmud tells us that Rabbi Akiva had the knowledge to expound on the meaning of the crowns of each of the seven letters of the Aleph-Bet that have crowns. In order to assure the accuracy of the transmission of the Torah it is necessary to see to it that each copy contains the same words, spelled in the identical manner, so that our tradition should not be lost.