I started to write a post about the limited Squarespace Chart Block— to really tear it apart. However, after playing for a bit, I'm actually thrilled with the usefulness!
The key is to import your CSV data (a built-in feature). Don't type values into the built-in user interface; there's just not enough space in the user interface to make it seem rewarding. It's also hard to imagine how the data will plot, so trust me— get it into CSV format first, then import it. (CSV Example)
If there's enough plotted data, it really gives new visual meaning to any story.
Seeing the Major League data example below was the A-HA moment. To view "payroll" vs "wins" on a line graph screams USEFUL. Hooray for data!
Major League Baseball 2012 Season
Hurricane and Tropical Storm Counts for 2005-2015
Rotten Tomato ratings of Robert De Niro movies ('68-'88)
Biometric statistics for a group of office workers
Monthly transatlantic airtravel, in thousands of passengers, for 1958-1960
View Squarespace's full documentation on the Chart Block.