Developing within/without architecture achieves the concrete business objectives; within the desired time period; with the desired quality and acceptable costs. Developing within architecture is the default. 

However, under certain circumstances, extreme time pressure for instance, the choice may be made to design without architecture. That being the case the Development without Architecture process will be executed. 
In this managed process, certain aspects will not be included, initially. Managed because in parallel, using a so called management letter, actions are undertaken to ensure that it ultimately be brought into an architecture. The “management letter” is a form of contract between the customer, project manager and architect which outline agreements related to the restricted life span of the project result and the concurrent launch of a structured process. 

The objective of designing within/without architecture is to do the appropriate things at the appropriate times.