A misconfigured AbuseFilter may result in a large number of meaningless hits (e.g. [[ https://www.wikidata.org/wiki/Topic:V8lpcrmxdqv6yo4t | almost all edits are reported]]). This will clutter the abuse log. It may be meaningful to hide the hits while the filter is broken.
Here is another use case: In Chinese Wikipedia there's once an abusefilter to tag all edits about addition tag of any kind. This means content almost all deleted pages were visible to all autoconfirmed users, and there're no ways to remove them other than Oversight (until T115530 is fixed). The abusefilter is currently disabled and made private, but rollbackers can still see the detail (per configuration in zhwiki). T44734 may solve it, but there seems no consensus to make abusefilter hits of deleted page hidden in zhwiki (In [[ https://zh.wikipedia.org/wiki/Wikipedia:%E5%B7%B2%E5%88%A0%E9%99%A4%E5%86%85%E5%AE%B9%E6%9F%A5%E8%AF%A2 | "Request for viewing deleted content" ]], abuse log is explicitly stated as a way to view deleted content).
This feature may allow user to hide all hits of a specific filter in a specific time range from abuse log. Once they are hidden, they (include their existence) are not visible in AbuseLog (even for admins and oversighters). Technically the log entries are not deleted; the abuse_filter_log table will include a new column ("afl_hidden'), which is a reference to the logging table. By querying the column, the hidden action may be undone.
By default, Details of hidden entry are not suppressed and are still visible in Special:AbuseLog/ID; they may still be suppressed (or revdeled after T115530) individually. For the second usecase, it's also useful to have the feature to restrict the viewing right.