In certain cases Cash takes on almost a freedom of speech importance. Government can just switch off the digital finances of any movement they don't like. Cash makes that harder.
https://www.theguardian.com/world/2023/feb/15/angry-protests...
Another recent example of a hard currency crisis is what's been happening in Lebanon, where the government simply switched off full access:
https://www.ft.com/content/a710fa12-e7fe-4aab-8e4f-962f01add...
I can disable your bank account rendering you unable to be personally solvent.
But in order to do so with the cash you have I would have to basically disable everyones account.
Also you can't access it in places without internet access or electricity (e.g. during wartime or as a refugee on the go).