Indeed, I also often use 'any' and 'all' in Time Settings modules. In the following example of Level 1 model, you want to identify Actual Period and Forecast Period, based on Current Period settings. If you want to filter your module and your summary settings would be set to 'None', you would not see FY19 for example. By using summary setting 'Any', FY19 will be true if any of the months of FY19 is true. However, using 'All', FY19 will be true only if all 2019 months are true.
You can play around and change summary settings in Level 1 model to see the impact. This is of course just one of example when you can use the two mentioned summary settings.
Please let me know if you have any more questions about this. Hope this clarifies a bit!