> A few hours later somebody digged out a pdf from an old archive but wasn't sure if it's the correct one, so we ran `ipfs add file.pdf` and the ipfs link started working again.

So the file was lost until it could be recovered from a different source and IPFS served the function of a glorified hash database, that's something very different from what it promises.

Bittorrent has the same mechanics with magnet URNs, but you never see them promising permanent storage.