Does deleting a realm have any impact on the site?
Deleting a Realm can have an impact on the site performance, especially for large realms where a lot of information is being deleted from the database. Very large realms should only be deleted during slow times, like the end of the day or weekends to avoid impacting site performance.
The realm deletion tool will check the publishing queue to determine publishing activity. The deletion task will pause and waits for things to slow down if more than 10,000 messages are in the publishing queue. It does not take into account other site activity, however.
If the Realm is small, you may not need to use the Blackout option when setting up the deletion process.