File Backups - Block Level vs Full
As matt stated, block-level file backups allow you to back up changes within files. This is helpful when you are working with large files (like an Outlook PST file) and do not want to back up the full file every time. Instead, we can back up the changed blocks within the file. if you have this need, then enable the option and the corresponding schedule to back up the full files as needed. if not, you can disable.