You type it so your message looks nice. Let’s break down exactly what this means. You are typing it because you think rendered Markdown is pleasing to the eye and facilitates comprehension of your words. So why don’t we just write rendered Markdown?
Markup languages are so simple that it’s barely worthwhile to look at the source code of your Markdown. This is especially true when doing creative writing. Your mind is in far-away thought places and Markdown syntax is cognitive burden. You are assigning semantics to symbols.
This is similar (do some research and get a good citation) to what you’re doing while you’re writing English. You are looking at symbols that don’t have inhereit meaning and you lookup their historically and culturally assigned definitions. Overtime this becomes an automatic behavior that has a low cognitive load. A new language (where language is loosely defined as some grammar used to express yourself) forces you to develop automatic lookups for a new grammar and this carries a higher cogntive load that interpreting your native tongue. This is an acceptable trade if the written form of this language is required for your audience to understand it (assuming you are not speaking to the receiving party). This may seem trivially obvious until you consider that othe people don’t understand your Markup code by looking at the language it’s written in. They read someone else’s interpretation of what you wrote. When you write Markdown you are having a conversation with a Markdown Interpreter so that that Interpretor (Leslie) can have that conversation with other people. You think Leslie has this knack for delivery that makes your ideas more compelling to other people and so you supply the material and they supply charisma.
That’s pretty crazy. A human deferring to a computer program his communication to humans. They do it because they think it represents their ideas in an way that is easier to parse and understand. So why would we ever write our content while looking at the source of a Markdown file? If we already do not think that it is the form most conducive for comprehension that why would we hinder our own comprehension. It is true that the author’s relationship with their content is different than the readers’. Isn’t comprehension part of the basis of any effective relationship?
So why not communicate with yourself with the tool you use to communicate with others.