Some events contain binary data, which is almost never read or analyzed by anyone, and therefore can be safely ignored. The "Ignore Binary Data" setting controls whether or not the EventSentry agent writes binary data to the database when an event contains binary data. Binary data has poor insert performance since it cannot be indexed, so it is not recommended to write binary data to the database unless this data would be useful to you.
Binary data is usually only used for software debugging or forensic analysis. Although the data can be manually analyzed, it is commonly analyzed with special tools and it is rare that these tools would need historical data such as the binary data which is stored in the database.
Here is an example of some binary data: