Interesting point here - vampirism (or vampyrism) on Discworld seems to fall into three different categories - there is the early one where blood is a necessary part of their diet, but can be satisfied by working in kosher butchers or slaughterhouses, there is the Carpe Jugulum version where it is about control, and there is the Black Ribboner version which treats it as an addiction.

Assuming that the last one is the current format, I fit into the "Sally" mould - when I gave up smoking about 16 years ago I did it "cold turkey", and when I went off alcohol for five years, I did the same (dual purpose - letting my body recover somewhat and proving to my friends that I was not an alcoholic ) - but that does not mean that everyone can, so Otto and Maladicta have their replacement activity, which is reasonable.
Before people think I'm getting too smug about my will-power - the odd few occasions I've smoked the wacky baccy at parties it has done nothing for me, and I certainly do not intend to rely on being able to give up and therefore risk anything eaten as a pill, shoved up my nose, or injected into my blood system!