Well put; the scope of usefulness of surveilance data lies well beyond what is in that data itself, but how it relates to other data. You don't necessarily need to decrypt data to distill value from it, as its metadata (location, datetime, medium, etc.) is also (and potentially more) useful when related with other metadata. Storing this data is also a monumental task, given the fidelity of records that many consumer devices create, store, and upload.