I've heard this before, so what I think it means is this: If you want to encrypt some data that gets stored persistently somewhere on your machine, rather than

I've heard this before, so what I think it means is this: If you want to encrypt some data that gets stored persistently somewhere on your machine, rather than invent an application-specific encryption scheme for that data alone, instead use a mainstream full-partition encryption mechanism, then store the data as plaintext within said partition.