Another is that cash is inclusive – it enables every one of us to participate in the money cycle and economic life. That's a hugely important feature for more socially disadvantaged sections of society, in particular. A third characteristic is that people can use cash no matter whether they bank online or have an account.
Detective vigilance comes into play before the outcome has actually been realised (this is shown in the schematic as the oval box around the outcomes H and L). Its precision is denoted by q.