I do care about the GP. It's the only complete international event before the Worlds,
Well, it's not really complete.
Some good skaters can't get GP assignments/invitations because they weren't able to earn high enough placements/world rankings last year. In some cases that's because they didn't have opportunities last year -- e.g., new pair and dance teams, skaters switching nationalities, 14-year-olds.
Each individual GP event has only about one-third of the top skaters participating in the series. And the final has only six qualifiers per event -- sometimes the alternates are just as good as the last qualifiers but suffered from competing in stronger regular season events. E.g., Arakawa in 2005-06.