ADDED: I was searching to understand this better. It may be from Jessie's response that mark down text is really mostly about HTML or similar online publishing of text fields. If true then the "standard" line break that I am seeking for printing out documents may not be in mark downs bag of tricks (read, TaskPaper). I hope not as it is very useful - especially in my case for printing out action results from TaskPaper.
I have discovered that for me I need to have a hybrid of creating, editing and organizing that includes both physical hand written notebooks and computerized writing, editing, searching, sorting, tagging, filing, printing, etc.
For example, when I am working on an article that I am going to submit I like to copy the text into Notes, put on headphones, print out the text, and go outside and have some cigar time while I listen to it being read back as I go over the text. I can catch more errors this way as the misreading of a word by the computer voice is letting me know of an error. It also helps to hear my writing in a different context.
And so, page breaks for printing are important. Here is a link where this was discussed in more depth than I can understand. Perhaps it makes more sense to those like Jessie who are more familiar with the mark down world?
Mark down and page breaks