World's smallest storage device lies in the nucleus of an atom

Probably, they mean they can use standard ECC to keep the information reliable. In the case of longer term storage, they would probably need to scan and refresh the memory periodically, like modern DRAM; using ECC would assure that the data written back is reliable. This is assuming, that the 1.75 seconds is an average and not a sure thing. If they could guarantee that the information would remain for that time period, I see no reason why it couldn't be treated like normal DRAM.