For me the benefits of this were almost entirely based on the chosen format. An expanded tournament could only mean more football, which, from my perspective, can't be a bad thing. That said, there are a few caveats.
In short, these are the formats from which the FIFA Committee chose:
1) A 48-team World Cup consisting of 16 groups of three, with the top two sides qualifying for a last-32 knockout stage (80 games in total);
2) Another 48-team version consisting of a 32-team, one-game knockout round, with the winners joining 16 already-qualified teams (80 games - 16 in preliminary and 64 in main tournament);
3) Expanding it to 40 teams, with 10 groups of four and only six group runners-up advancing (76 games);
4) A 40-team tournament with eight groups of five (88 games);
5) Keeping the World Cup at its present size of 32 teams (64 games).
Assuming option 5 is unavailable, my perspective is:
- I don't like the idea of odd-numbered groups as it increases the likelihood of collusion.
- I don't like seeding as I like all teams who have qualified to begin on an equal footing.
This rules out everything except option 3.
Naturally, FIFA went for the option which includes the most matches, and henceforth, the most money, and sod the consequences.