Process is good. Dogma is bad.
Following a process is great. It gives you many many benefits, from predictability to a framework for thinking about problems to rules that prevent infighting. However, processes are subject to the real world, and each implementation needs to be flexible and tuned to your needs.
So, what is the purpose of having a process like XP or SCRUM?
- Provide consistency. Having a process will help you do things the same way each time.
- Take advantage of others' mistakes. Every process was created over a number of years with numerous mistakes that were corrected - and you get the benefit of it.
- Ensure smooth flow throughout the development process. Having a process to provide rules and checks prevents developers fighting with marketing, developers fighting amongst themselves, etc. Normally, this shouldn't happen, but sometimes having the process is nice.
So have a process. Follow your process. But don't forget that process isn't the point. Shipping your software is the point.