For a greenfield project that's fine - solve the issues that come up as they come. Someone is getting value right away.
Code you throw away makes the most sense to me for prototyping cross-cutting features in existing systems. A lot of companies can accumulate a ton of crud in only a few years of development time, and it follows Conway's Law that the crud is shaped like the org tree. Writing a throwaway feature end-to-end helps to identify the interfaces between the teams and subsequently components of the software.
This is also why I'm a big fan of assembling project teams over having teams "own" an area. Everyone on the project team is responsible for the project working well. Otherwise every team is worried about their small domain.
I've had code I threw together in 10 minutes end up in production after putting it in a 'temporary' repo.