Just curious, all Wager Master's Condition cards are indestructible as stated on both side of his character cards. All Drug cards are indestructible as state on the Drug cards.
For consistency, why not write the indestructible text of Drug cards on Spite's character cards instead? Are there any scenarios where the different placement of the indestructible text comes into play?
Sprites Drugs say that they can't go into the trash however condition cards can go into the trash so that might be why
Sapienta potentia est
No, they could still write it on Spite's Character card. Rules-wise, it would be exactly the same. However, it matters a great deal aesthetics-wise.
Aesthetically, you want to have as few words as possible, both on each card, and in the game itself. This is because space is limited, both in the minds of players and on the cards themselves. A card can only have so many words before it runs out of space. On character cards, more space can be claimed by making the text box bigger or the font size smaller, but that obscures the art or the text respectively. On other cards, text box size is fixed, so once you run out of room your only alternative is to make the text smaller. Also, a player can only keep track of so many rules at one time, which is why it is beneficial to have card types that all behave identically. Putting the text on the character card indicates that it is a blanket effect, and speeds up a player's ability to become familiar with the cards. On the other hand, putting the text on the cards indicates that the rules do not change when the character flips, which is also advantageous.
In this case, I think that the difference is more about physical space than mental space, though.
In Spite's case, his drugs have very little text. They are still easy to understand even with additional text, so it is advantageous to leave the text there rather than taking up picture space on the character cards.
In Wager Master's case, his conditions are very complicated. There is very little room for additional text, so it's placed on Wager Master himself.
"Do you not know that a man is not dead while his name is still spoken?"
- Terry Pratchett, Going Postal
Rook City was the first expansion. If they made it now, the rule about drugs would probably be on his card.
Compare Matriarch, who had to have the rule for chaining fowl cards moved on to her character card. It was originally on the fowl cards themselves, and that allowed for some exploits.
The point isn't that Spite's drugs allow for exploits, just that the tendency when they wrote Rook City was to put rules on individual cards rather than on character cards.