This manga really feels like a throwback, "monster of the week" type stuff from the 90s. I mean honestly they might as well be chasing the "shikon jewel shards." There's an overarching story but it's made up of little short stories stitched together. I think that's part of the appeal, for me at least.
It feels different from what most popular shounen or otherwise do now and maybe that helps it stand out to younger viewers too (besides other things it does well). Every week, or every couple chapters is a whole new world. It feels nostalgic in that way, sometimes.