Because you are going to select different phrases and words while speaking than you are when writing. Even with context clues from the conversation, it can at times be confusing, so you have to explain what you meant. Usually it's verbal, sometimes it's 空書 (sky writing). To avoid having to do this frequently, people will often adopt a subset of the language that is less prone to confusing homophones for their vocal communication.
It creates a situation where you have people who have wildly different voices in their writing than they do in their everyday speaking, which is an interesting phenomenon. (To me, at least)
It creates a situation where you have people who have wildly different voices in their writing than they do in their everyday speaking, which is an interesting phenomenon. (To me, at least)