I personally don’t need it…
…because I was lucky enough to track down a complete physical set of the game line in the 1990s. A combination of ample discretionary cash and ready access to NYC’s gaming stores allowed me to devote resources to find some of the more esoteric stuff, which Castle Falkenstein certainly is. Castle Falkenstein is… it is the distillation of all that is romantic and fun about steampunk. It is a 19th century world where historical and fictional figures meet all the time and have adventures together, set in a backdrop of magic, zeppelins, and dramatic reveals. And, oh, yes: the game uses playing cards, because while ladies and gentlemen might readily amuse themselves by pretending to be cowboys or mages for an evening, they will most certainly not use dice to do it.
I love the Castle Falkenstein setting dearly. And, not to brag (I totally mean to brag) I also have a playtester’s credit for the GURPS edition of it. So while I don’t need these PDFs, there are worse ways to burn through twenty bucks than to get the complete game line…