Uh, I suspect a lot of private trees were made that way after doing hours and hours of work and paying $1000s of dollars in records access fees and records images and DNA tests and then discovering the 1st month they don't continue to pay ancestry.com for access to those records images they paid so much to access and linked to their trees that they no longer have access to those researched and linked records. They actually have to go through all this extra work of downloading the record image and embedding it like a personal photograph at which time it looses all the text translations and corrections other users have made to some of the entries as well as the original link to the ancestry.com tree.
However, from a purely independent point of view, the census images should be downloaded and embedded into your tree and then manually add the needed relevant references and notes since ancestry.com doesn't have to respect for their customers to have designed it that way. No one pays $20 a month expecting all their hours of work to disappear with a bunch of already researched but broken links in your family tree.