[brudgers]

The Taco Truck gets one thinking about a concrete example and looking at its processes. Unlike a bank, any software solution for a Taco Truck is likely to be generalizable across a large range of businesses [whereas a bank might get one thinking about something as narrow as international wire transfers].

Look at the examples given in other comments - inventory, vehicle maintenance, planning - if a Taco Truck could use it, a lot of other businesses can too.

The danger is coming up with a Taco Truck specific payment handling solution rather than a generalized one. The Taco Truck Solution leads to an email feature implemented in a subset of Common Lisp. The generalized solution leads to Stripe and competing with PayPal.