There is an underlying grid system to vertically align the bars nicely.
By default it consists of 4 bars per row.
A line with just one bar/chord is only a quarter of the page width.
Two bars use half the width and so on.
If you add more than 4 bars they will become narrower. And if you add too many bars in a single line, it may become unreadable. To avoid this, just use more lines. It's best to use 4 bars/chords per row.
The global default value for the number of bars (nob) per row is 4.
Example (nob = 4): We Have All The Time In The World (Louis Armstrong)
But sometimes it's useful to choose a different value.
To keep the bars vertically aligned if there are some added extra bars in an otherwise straight 4 bar per row progression.
Example (nob = 5): Nothing Ever Happens (Del Amitri)
Example (nob = 6): And I Love Her (The Beatles)
Example (nob = 8): Who's Gonna Ride Your Wild Horses (U2)
Split bar changes with just two bars per row.
Example (nob = 2): True Colors (Cyndi Lauper)
To get a larger right margin, e.g. for annotations.
Example (nob = 6): Your Song (Elton John)