There was no need to use the yellow tracking dots to track Reality Winner... the NSA would certainly have the ability to audit anything printed in their facility and know exactly what was printed on any given day.
The reality is even in corporate environments print servers for sensitive areas will retain audit logs and/or copies of documents sent to the print spool. Even if that completely fails, you can do a forensic recovery on the hard drive inside the printer where all documents are buffered.
> Maybe she thought physical paper would be safer from digital surveillance than an email. So she printed the documents at her office [my emphasis] and then mailed them