"Prevents Outlook from blocking unsafe attachments"
Attachment Options avoids the blocking that Microsoft Outlook applies to attachments that the email client considers to be dangerous. So, without altering the O.S. Registry, you will be able to deal with EXE, BAT and other files without being prevented by Outlook.
Enabling Attachment Options will unlock any file that Microsoft Outlook thinks is dangerous through the e-mail client's own menu. After doing so, every email you receive with a file considered risky opening will be freely treatable by you, being possible to open it or delete it directly.
Attachment Options does not edit any entries in the Windows Registry, so it will remain unchanged despite the change it makes to the operation of Microsoft Outlook.