Outlook 2016 has a modern attachment feature that allows you to add attachments or links to files stored in OneDrive. You can set permissions on the file shared through OneDrive, as you add the attachment to the email message.
If you want to send it as an attachment instead of a link to the link on OneDrive, expand the menu and select Attach as copy. The cloud image on the icon disappears when it's converted to a traditional attachment.
As of Office build, 16.0.6366.2062, it is possible to select one or more attachments and delete all at once.
While you can't drag the mouse to select a group of attachments (as you could in older versions), you can use the Select All command on the attachment menu, use Ctrl+A, or click on the first attachment then hold Shift and click on the last. After selecting the attachments use the Delete key or the Remove Attachment command on the attachment menu. Hold Ctrl as you click individual attachments to select some, but not all, attachments.
Other problems users are complaining about include the attachment icon in the header is huge. It's not too bad if you are using a touch screen, as it's an easy target for big fingers, but the attachment row is twice as large as it needs to be for desktop users. You can hide the attachments in received messages by clicking on the paperclip on the right side of the header (near the message date). Click the paperclip again to show the attachments. While it's nice to hide the attachments, I would prefer smaller icons so I don't need to hide them (and forget they are hidden!)
Another problem is that you can't insert text files as text. This was a favorite feature of many users, as they could use it to insert prepared text files. I have a macro that can replace this function.
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