First Aspect
Squire
It's just that the graphical element of the triangles to explain in three separate 'graphs' doesn't add anything other than three prettily-coloured triangles saying that three-say heatwaves might peak on the first, second or third days. Well, duh. The second graph says that longer heatwaves are, well, longer, and might peak in the first, second, or third parts of the heatwaves. But at least the shapes of the lines do convey a bit of extra information beyond the categories.
They are intended to depict a general principle and show how the observed data reflects these principles.
For some, for examples peolle who generally understand how an oven works, these general principles are pretty simple. For others, for example a large proportion of the electorate, this "If I have two beans, and add another two beans" approach is entirely necessary.