The claim sounds rather dubious.

It assumes cell phone towers would still be in operation during a major power outage so you can still use your phone apps
and perform your financial transactions. If the cell towers in the effected area have backup generator power they can
keep cell phone service going.

In that case many things will still function through your cell phone, including bitcoin transactions, so CBDCs don't have any
special advantage. Many businesses, especially larger ones, have backup generator power so they could still be operating
during the outage at least temporarily. It's a dumb argument for CBDCs.