[Spooky23]

The first example undermines the argument. It’s a demonstration that the author doesn’t understand a tool.

That pie chart tells me that the slices are approximately the same, which is a useful message to effectively deliver visually. Pie charts are great for understanding relative value.

Divining or comparing the precise values is not a good use for it.

[edflsafoiewq]

So does the second. It shows you almost immediately that about half the precipitation falls on the weekend, validating the claim, which is not at all clear from the bar chart.

[Supermancho]

It's less and less common to see pie charts without the specific %/values anyway. This is some sort of silly hangup by the author(s).