A backup/offline version would be pretty nice, but PDF format???
PDF is neither good at representing structured data, nor is it easily editable.
Additionally, it's not meant to interpret by machines, which makes writing applications for it difficult (which is probably what you want, unless you want to update/import your list by hand).
Basically, unless you want to print your data on paper, PDF is a terrible format to export it to. Something more sensible, like say XML or even CSV, is much preferred.