Why do they make indents on the sides with a small screen?

Question

Layout

DD.
Bootstrap example getbootstrap.com/docs/4.0/examples/album

This is when the screen is < 1024, why not make the width 100% when the screen is small? I understand that they have everything on a percentage, but I don’t understand why such indents on small screens?
Are there any pitfalls if I make 100% width when the screen is less than 1024px or 1000px?
Thank you

Answer 1

So that you can scroll from left to right without fear of clicking on a hyperlink.

Answer 2

Why not? :)