Markup languages.

Which were done as such to allow people to write a sentence on each line in their editor, remember notepad etc. doesn't wrap lines so you've got to scroll all the way over to read your lines.
This became the de-facto way of formatting most things, and it's easier to do newlines like that than using a br tag (and html tags generally) which are cringe af

Note you can also do a smaller newline with two spaces at the end of the preceding line