|Access & copy what & why exactly - huh?|
You start the recovery process by booting from a recovery disc associated with the tool that was used to create the partition. This is not very different from the recovery method synonymous with many OEMs, except, they tend to hide the recovery partition for PEBKAC reasons - which is understandable.
Arguably, the most reliable way to secure sensitive data, is to deploy copies of such data at multiple off-site locations simultaneously. Moreover, such a plan is not infallible in & of itself; only that the probability of a data meltdown is extremely minimal. Anything less than that has an element of risk associated with it.
A secondary backup drive isn't immune to mechanical defects or total failure; optical media degenerate over time; thumb drives go bad without warning; even a whole damn house full of computers can go up in flames.
Since there is no perfect plan, even a less than robust backup plan is much preferred to none -- I'd rather have someone create a secondary partition for assorted important data, than accept the argument that the whole disk is indestructible & therefore not worth implementing a contingency plan around.