#2 To bring the seriousness back in the division
The video above sums it all up. The tag division was always relegated as a sideshow. Even in the past, when serious tag-teams like the Road Warriors were the champions, the division was never taken seriously enough.
Both RAW and SmackDown's tag division is out of sorts, and there's no way that the tag championship features as a major storyline going into a PPV.
While the tag championships headlining WrestleMania is too optimistic, it needs to be taken much more seriously.
The reason tag teams from around the world are joining AEW is that they offer a better focus on the tag team and women's division, similar to men's singles. While AEW is an unproven commodity, it's still clear where their focus is.
With Bryan involved, the tag division is sure to get a boost storyline-wise. A one-off match against the Usos is a good start.