A 20% increase in my curation reward means nothing to me

It is actually a doubling of curation reward. The current asymmetry between 75 and 25 introduces a leverage effect where shifting reward from author to curator means a lot more to the curator percentage-wise than it does to the author.

It is true that for the very smallest stakeholders, even 2x curation reward won't even be noticed (and may still round down to zero and still not be paid at all), but there are many in the middle for whom this will be a very significant increase and encourage more attention to curation, even if not whales. It is also more of an incentive to power up and increase your curation rewards.