While having a discussion with a friend who oft malapropriates their/there/they're, and to/too/two, he maintains the position that he has a:
"disbelief that the current system is the best one"
He contends that all that is necessary is a single word, say, 'ther', that will accommodate all the uses and that since the context can be gained from a spoken conversation, that a "better system", in his view, would be a system with just the single option - essentially, collapse all homophones into single words with the same orthography, but with combined definitions.
I don't share this perspective; I find the written word to be a superior form of language than spoken, and detest the bastardization of linguistic rules by people who can't be bothered to proofread and follow grammatic and syntactical rules.
My sentiments aside; what specific reasons are there to persist variant spellings of homophones?
He's also made reference to the supposed 'inefficiency' of having to learn and use the variant homophones:
"I do not refuse to learn, I just will not go out of my way to re-type, or proof read something when I feel it reasonable that it will be understood. Also, I feel that its requirement is not necessary and the rules should be amended to simply and expedite conversation."
So - what are good linguistic reasons to retain the heterographic homophones?