In the default setting, TeX is formatting a text with the fully justified mode. In contrast, the screenshot shows the opposite which is called left-justified text. The open question is how big is the difference? On the first look there are some white spaces at the right edge, but not very much. It seems that a normal line wrapping algorithm makes sure that in average the right side looks smooth. But let us take a closer look into the example.
The paragraph on the left are mostly correct formatted. That means, no visible space or only a smaller one is available at the right edge. In contrast the left page has some visible spaces. The cause was that the word was wrapped to the next line and no hyphenation or character kerning was applied. But this affects only 2-3 paragraphs and not all. So we have to ask what exactly is the advantage if the entire text gets formatted fully justified?
The interesting situation is that the situation will become more complicated if the text gets blured. If the reader will look fro the distance to the layout it is harder to see the advantage of fully justified text.