Barcelona had a fantastic 2024-25 season, although it would've been even better if they won the Champions League (they were the favourite).
Real suffered a bit of humiliation, especially considering they lost all direct games against Barcelona (El Clásico), but they still have a chance to salvage their reputation and make their fans happy by either winning the FIFA Club World Cup or, at the very least, achieving semi-finals or the final.
The prestige and the prize pool of FIFA CWC is similar to those of the Champions League. I believe the total prize pot is around $1 billion, so not something to be ignored.
How was Barcelona the favourite for the Champions League last season. There can never be only one favourite for it. If you had said, Barcelona were one of the favourites then it's very valid. Liverpool was seen as one of the favourites but exited earlier in the competition. PSG was one of the favourites as well, same as Bayern Munich too. All I'm saying is that, there cannot be only one favourite, there's always two or more favourites to win a competition.