Many ways to build systems
Differing philosophies and incorporated methods lead to different ways to create a system. Having simple documentation describing the steps you take when developing systems reduces confusion, saves time and keeps the whole team working together well.
Each workflow has project scales where it is more suited and others where it is less suited. For example: you may have a great workflow defined for developing that mobile application or the organization’s website but it might not payoff when developing that automated backup verification script that will take about a day to create. By documenting when a workflow is to be used and when not, you keep your whole team on the same page.
One for each scale
Having a few workflows defined for differing scales of projects allows an organization to move forward quickly with everyone using the same process. All you have to do when you have a new project is to estimate the time it will take, from there everyone will know which workflow to use. It’s like corporate traveling guidelines many companies use: if less than 4 hours drive time, drive. If over 4 hours drive time, fly.