I was in a premade tonight and in a couple of the games, my Battle Standard of Coordination (10 min cd) was still on cooldown from the previous BG at the end of the BG, so I could not drop it.
So I went and bought Battle Standard of Unity and it turns out that it only gets a 2 min cooldown when you drop the other banner. So by having both in your bags, you can make sure to get the extra honor every BG because there will always be one off cooldown.
And if someone still doesn't know yet, these banners do give you bonus honor at the end of battlegrounds.
This is nothing big, but it can be useful I believe =)
Hope this helps someone!