What will happen If we use only ひらがな/カタカナ(hiragana/katakana) in Japanese sentences?

漢字(kanji: Chinese character) is the most difficult part when studying Japanese. Many foreign learners may wonder why Japanese language uses so many Kanjis, even if it’s possible to do only write sentences with ひらがな/カタカナ in writing sentences.
What will happen If we use only ひらがな/カタカナ in Japanese sentences?

I’m sure Japanese sentences are not sufficient if they are written simply in ひらがな/カタカナ.

Reason 1
ひらがな/カタカナ are created to express Japanese original words （大和言葉/和語: yamato-kotoba/wago）and we have a number of China origin words, *originated from Chinese (or; words of Chinese origin)（漢語: kango）. If we use ひらがな/カタカナ to write China origin words *, it takes more time to read because we have to search for appropriate 漢字 **in our brains.

Reason 2
Japanese pronunciations are is relatively simple and there are many homonyms such as; NIHON （日本/二本）,HASHI （橋/箸）,　HARU（春/貼る）. Without 漢字, it’s sometimes difficult to tell which of the meanings a writer wants to say


I think 漢字 plays a role to compensate for the insufficiencies of Japanese pronunciations. In other words, Japanese language relies more on Reading/Writing than other languages. This can ***could also explain why Japanese's**** literacy rate is almost 100%. We often imagine 漢字 which fits the words in our minds when talking with others in order to help understanding.

Japanese language cannot be made up without 漢字.

* It is the exact situation for both parts in the sentence. Also note, that the adjective of the matching country is not the same as the country itself most of the time

** Although grammatically correct, it would almost never be used in a sentence, except, if the context would require it. A better and easier way to say this would be "... because we have to think of appropriate 漢字", since you have the information with "searching for something in the brain" included.

*** "could" instead of "can" would be the right conjugation if you want to make a suggestion, that explains the following part. However, if you want to give the exact reason it would be "This also explains ..."

**** You probably mean the literacy rate in the country Japan