They have a list of reasons to expedite on the website, severe financial loss due to wait, humanitarian (people in war torn countries have been denied so it has to be extreme not 'things aren't ideal'), US government interest, USCIS made an error.
The financial one is a very niche case and generally all expedite reasons have to affect the petitioner not beneficery. Obv you can try but generally approved expedites are due to petitioner having deployment orders
Also reminder the expedite reasons on the website are for *all* visas so for instance the financial loss one is mostly aimed at employment based visas, not a k1/family visa