TEX was invented, in order to be able to create high quality printouts with the computer. The goal was to be able to process books and texts of all kinds by the computer, in a way, that they look pretty. This however, does not per se mean the resolution of the printer. TEX typesets texts in a way that they are aesthetically pleasant.
This craftsmanship was only known by typesetters in the past. Normally you need a good education and a sizeable proportion of experience, to fabricate good looking texts. E.g. a text is pleasant to read, when not too many kinds of typefaces are used on a single page, as otherwise the brain can not concentrate on the text properly. Exactly the same is the case with empty lines, to structure a text. These are merely simple basic rules. Typesetters know hundreds of them, and often, texts produced by professionals just look better than others. Sometimes you do not even know why, but they simply look better. Typesetters were additionally also able to correct mistakes of the author – what sometimes led to newly introduced errors.
Now, as a private person with little time and without being equipped with this special knowledge, you still want to print good looking texts, this program is supposed to relieve you of many details. TEX is very friendly from this point of view and – unless you do not want it to – takes most of the burden off of you. This way you can concentrate on the contents.