I would like to have the Option to download the attachment. I have seen when others like the attachment opening in a separate window. However, there are times when you would like to download the attachments: for example, to add a new page, to update an existing page, etc.
You can download from the browser extension and from the Desktop app, but interestingly, it seems that the Web Vault does not have a download option for the file types that have an embedded viewer.