Flash and pdf

[vasa1]

Both Flash and pdf have been known to be targets of bad people. I just came across mention of a Flash-based pdf file reader: Doh! WikiLeaks' PDF viewer springs XSS vuln (http://www.theregister.co.uk/2014/12/23/wikileaks_pdf_viewer_vuln/)

[pqwoerituytrueiwoq]

Would someone explain why anyone would want a PDF reader written Flash for anything other than a OLD school project (you know cause nobody should be learning flash anymore)