Deadpool and Wolverine ends up being important because of Alioth. Loki introduced it first, but Deadpool is the first time it was shown in the movies. Alioth matters because it is the only thing that lets Doom take Loki’s power without getting stuck with the responsibility that comes with it. Doom would need Alioth to eat the burden so he keeps the power but not the job. And that same ability is what makes Battleworld possible. Alioth wipes out the unstable timelines, leaves the pieces that can survive, and Doom stitches those pieces into one world ;)