Scripts being the main driver of literacy is a pet peeve of mine. It's not the script, it's the schooling system. The high rates of literacy in modern states are just a result of the school system - Japan has a high literacy rate, for example, and their writing system is either the worst in the world or close to it.
That said, the characters are a whole boatload of unnecessary extra effort, and as a student of the two languages, the artificial illiteracy created by kanji, where I often just can't read words I've known for years, is simply maddening. Not having to wrestle with characters does free up a lot of time for both native and foreign students alike.
>their writing system is either the worst in the world or close to it
Yes, it's probably the worst since even Microsoft until now still struggle to provide proper search solution for Japanese names in their Windows OS due to their multitude of writing systems.
By sheer wills of course you can make everything hard feasible but that does not means it's efficient and effective. I consider Japanese as a unique country with extraordinary people that can collectively overcome adversity, that's include a non intuitive and difficult writing systems.
That said, the characters are a whole boatload of unnecessary extra effort, and as a student of the two languages, the artificial illiteracy created by kanji, where I often just can't read words I've known for years, is simply maddening. Not having to wrestle with characters does free up a lot of time for both native and foreign students alike.