It's a fair point. An interactive stacked area chart or a dot matrix would give you the freedom to focus in and to take away a lot more information about specific trends.

My counter would be that there is more to data visualization than the quantity of information communicated. If that weren't the case, all data would be shown as numbers in spreadsheets.

This data involves population counts spanning several orders of magnitude, for 72 countries over 20 time periods. It could be shown in a chart, but one that would require some patience to figure out.

An animated map requires no reading of axis labels, no analysis of abstract lines or shapes. The meaning of everything is plainly evident. And for the minute it takes to watch, the information content is actually very high.