Charity X: 95% of money donated goes to the cause.
Charity Y: 100% of money donated goes to the cause ( but we get an extra 20% from some where else).
Charity X, incentives are aligned to minimise administration spend. Charity Y obscures that link.
I imaging the admin is covered by corporate donors/payment processors waiving fees and claiming it all back on tax
And you start getting all kinds of perverse situations. What happens if they have funding to take $1 million in donations, but they get $2 million? Do they return donations?
What happens if they can't get enough admin donations? Do they stop work? Regardless of how much money they have in the bank, waiting to go to good causes?
Then there's the issue of splitting your fund raising efforts. Instead of telling everyone 5% of their donation is going to admin. You have to have a distinct team of admin fund raisers.
So to answer your question I would care if their admin spend was high. And the current set up obscures what that spend is.