I work in K12 IT, and the reason is that all manner of categories are defined for both blacklisting and whitelisting when creating content filter rules. So while “education” would not be used for blocking, it would be useful for rules to apply to specific defined groups or devices which can only access specific categories (such as education). Just FYI.
Categories such as “education” are useful for limiting access for specific groups of devices. For example, if one class has a particularly mischievous group who keep going off task from their devices, rules can be created to whitelist certain categories, and only pass traffic that are in these more straightforward categories. Just FYI.