writing is SUPPOSED to be a from of communication, but
when the person writing fails to adhere to the rules about how it works, the message is NOT communicated. Punctuation can seriously change the meaning of a sentence, and proper capitalisation can also do that as well as make it clear that the i was a lazy I and not a typo with a missed t or s for it or is. It makes no sense to deliberately mess up the message by not using the rules.
Example of punctuation changing meaning:
Help your Uncle Jack of the stallion. - - Help your uncle jack off the stallion.