I know before the pdfs where not usable as a standalone since cards with important information where not included.
But seeing the price for the new Enemy-Pdf and the fact that DrivethroughRPG does not have the "not complete"-text attached, is this pdf sufficient to play the campaign?
I don't know if the pdf includes further information from the cards, but most of the non-book bits from the new box were nice-but-not-required elements like location and clue cards, or repeated components from other boxes (e.g. monster cards). The questions and traits from the background cards are repeated in the book, but the once-per-session abilities and creation bonuses aren't.
The campaign would be perfectly playable with just the book imho, there might be a couple of loose ends but nothing game-breaking - you'd still get the npc stats in the appendices, etc.
At half the retail price of the box, I don't think it is a bad deal.