The Boolean property type can be used to store True or False values.

For example :

Collecting application details from your users. In order to segment the users who have shared all the details(completed the application), you can set up a boolean property like "Application Completed" as true, when all the questions are answered by the user.

You can use this as a conditional check in Branch block and set up separate flows for these users. Also in the Audience section, you can filter out all the users for whom Application Completed property is true.