Modern means of communication requires us to write every day. Often, the first introduction you have with a person is through the written medium. It is your first chance at making an impression. And this is where a lot of people fail, even smart people. Not capitalizing the first letter of your name and surname, bad spelling, lack of punctuation, poor grammar, all these are sure-shot ways of ruining that first impression.
this all depends so much on context! if i want to be regarded as professional, and qualified, then sure. if i'm talking to, like, my tattoo artist, or someone that i want to be familiar and comfortable with, then what does it matter if i don't go out of my way to capitalize words?