As Sonya_Forest said Japanese has a lot of meanings in the same pronunciation. So we can understand the meanings from　漢字。 And if you meet the unknown word but you know that kanji, you can guess that meaning of new word. I know how you feel kanji is very difficult. Because I have studied kanji since I was 6 until 18 years old in school even I'm Japanese. I hope it helps you ：）

In Japanese there is a lot word which can be written the same kana. For example, あめ means "rain" or "candy". Its pronunciation is different. How will you know which meaning is correct? So, 雨　- rain, 飴　- candy. @_@ ----- Sorry, if I made a mistake. English is foreign for me. 漢字はとても難しいが、面白いです。

because they are still used in Japanese language if you read a Japanese book and see 漢字 -- what will you do? however i think in the future they will kick them out of language because the excuse "different words with same pronunciation" never happens in oral speech if someone says "i want to eat あめ" no one thinks about eating rain :D