One of the defining characteristics of human society is the use of written language. A standard, codified form of written communication is essential in the very definition of civilization. Standardization is critical because if people just went around spelling things however they pleased, no one would know what the other was talking about. The middle ages were Dark for this very reason. Communication is impossible unless both parties understand what is meant by the written words. It is not sufficient merely to have characters to represent each phonetic possibility because of the presence of homonyms in the spoken language. Verbally, two words may sound the same, and the definition is inherent in the context. But on paper, without the benefit of inflection and phrasing cues, the meaning of a word is given only by the accepted understanding of what that combination of characters means. Punctuation and word order are also critical in extracting meaning from groups of words and letters. These definitions can be found in a document called a dictionary, the contents of which were agreed upon a long time ago in order to clear up any misunderstandings about the language. When people don't spell things correctly, or intentionally use the spelling of a homonym, the meaning of their sentence is lost. Secondly, Arabic numerals were adopted by westerners for the purpose of representing numbers mathematical calculations with them, not for representing English words that sound the same way the numbers are pronounced. But even the usage of numerals in prose is incorrect. The proper thing to do is to spell out the word for whatever number you want to describe.
What I'm getting at here is that when you use the written language incorrectly, no one can understand what you're saying. In this age, with the internet forcing more people to have to use the written language for more things, it is critical to uphold the standards of that language. Tell me what you want to tell me. The way to do that is to use the words that mean what you want to say, not just any random combination of letters that roughly resembles the phonetic interpretation of your comment.