When you have a not so large number of columns and/or a not so large screen, you have to scroll horizontally to view the remaining columns. I believe this occurs easily and frequently and, at least for me, it is annoying and I believe that having a (or a close to) full view of all the columns improves awareness and information access.
A very simple way to fix this is to somehow limit the container width and perform vertical scrolls. In Trello I have a Chrome extension to apply this using CSS tempering and works pretty well.
Just my 2 cents