Knowledge needs to be recorded and Quran is the Word of Allah and must be recorded in a complete book to :
1. Preserve Quran from any change which some people may try to cause for political or other reasons. No doubt, Quran is preserved by Allah and no power can change Quran.
2. Make it easy for Muslims to recite, study, memorize and follow the teachings of Quran.
3. Make it easy for those who want to know about Islam to read Quran.
Quran is available in the form of book, as well as in the internet and digital forms.
If you feel that your question has not been answered because you meant something else, please write your question more clearly.