Are documents permanently deleted after 30 days when they are sent to the Preservation Hold Library?

After configuring a Hold in the Office 365 Security and Compliance Center I saw that any matching documents got copied to the Preservation Hold library as they should when they got deleted. When I look at the Information Management Policy Settings of this library I noticed that there is one configured to Permanently Delete documents 30 days after the Date Preserved. Does this not defeat the purpose of a hold? Can anyone confirm that the documents sent to the Preservation Hold library do not get deleted after 30 days?