As I see it . . .
Think of 'Briefing' a bit like 'Notifications'. If you turn off 'Notifications' on your phone you won't see a light come on to tell you that you've missed a call, text or email. However if you check your texts, emails and missed calls all of those things will still be there.
Similarly if you turn off 'Briefing', apps which would otherwise have fed information to it (such as newsreaders, social media or weather apps) won't be able to do so. However if you access those apps directly you'll still have the information available anyway.
Turn it off!