Huge field MTTs on Stars - why bother?

When playing an mtt with about 300 runners, finishing exactly in the top 1% (i.e. 3rd) yields a return of something like 25-30BI.

When playing an mtt with 3000 runnners, finishing exactly in the top 1% (i.e. 30th) yields a return of something like 6-8BI.

Assuming equal spread of villain ability in each tournament and identical structure, why would we play tournaments that last longer and with much greater variance?

I kind of know the answer to this (and realise it may seem like a dumb question), but interested in what others think.