Well, it depends.

If you're compiling a report for a college group project (or the workplace equivalent of that) you might well need things like equations and tables and suchlike.

For example if you've got a table of performance results with the best performer in each row highlighted in bold, a fact the text references - then separating content and formatting doesn't really make that much sense.

> For example if you've got a table of performance results with the best performer in each row highlighted in bold, a fact the text references - then separating content and formatting doesn't really make that much sense.

You can tag the text as "important": see <strong> vs. <b> in HTML.

Just an example. Obviously the more formatting control you need the fancier your language and tool is. Tex is the upper bound.