The main reward for a guild or player that's not making much headway is simply these (i have 2 so far):
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It'll be curious to see how that works out. It seems like the Pass (where I got the above from) and Championship-End rewards might change with the championship no matter what you pick. So the choice would only be for the fragments you win by random chance (which do seem quite sparse - though at least in part for me that's because they're nonexistent in the first difficulty) and round-end chests.