Typically used to show trends over time, the slope of the line between two points shows patterns of change.
Learn to draw lines wherever and however you want, and you've got yourself some flexibility.
When you plot a lot of data at once, points and lines can obscure others and hide patterns. Transparency can help reveal what is really there.
Time series charts can easily turn to spaghetti when you have multiple categories. By highlighting the ones of interest, you can direct focus and allow comparisons.
There are good reasons to cancel cable, but there were a few channels and programs that kept me on. When you look at it in dollars though, it's hard to justify the value for the cost.