>>33821699No BW2 was a sequel, it was made clear the events of BW had happened before, and that you wren't playing through them again, but playing through what happened next.
USM isn't a sequel; you still find Lillie with Cosmog, you still fight Skull and Aether, etc. it's a third version. That's not to say it's objectively bad, third versions can be good, but it's not comparable to BW2