As a student I would love if this resulted in more software portability in education spaces. As it stands, half the classes I take only want Microsoft proprietary formats (docx pptx etc), which results in me having to use a giant nasty WYSIWYG editor that supports those formats like LibreOffice instead my preferred tooling (heirloom-doctools / troff, mandoc, or even better, plain text). At least some classes support PDFs, but I've yet to see a class that takes plain text submissions. Formatting documents wastes so much time and data for no real reason.
I disagree, if only for the reason that you can't easily and more importantly reliably convert document formats to plain text. On the other hand, there are plenty of good tools to convert plain text to printable formats (like pr from POSIX).
I don't think there was a time when formatting wasn't important.
From double spaced text to allow edits, to certain margins, to sectioning, to indexes, to appendices, to properly italicized bibliographical references, to page references etc.
It assists you in conveying your intent as the writer and if standardized it makes it easier for the reader (ie your teacher) to orient themselves with minimal effort. Similar to having a consistent user interface.