AnxiousSeal95 I see what you're getting at, however this is more of an automated devops task and less of a server feature - in general, we're always much more careful when deleting stuff, and it's always advisable to have separate processes for backup and deletion that can be externally controlled, maintained and monitored.
Hey DilapidatedDucks58 !
These indices are not mandatory, and basically provide historical information on worker statistics and performance that is displayed in the workers and queues page, and is also available for debugging and optimization purposes.
You can safely delete them (also periodically using a script, if you'd like). From what I see you're more concerned with their size on disk and no from the number of indices (1 each month)?