Filling the backpack
At the start of your career your backpack with is filled with lots of theory and as your career progresses more and more experience get’s thrown in, perfect. At some point you won’t be learning new things if you keep doing the same role. That’s why people take up different roles and grow in a team. However, the goal of the team’s you’re in often remains similar: develop system X that realizes user stories Y and Z. Many people do lots of roles, but all on the ‘producing’ side of the IT. I personally experienced the value of jumping to (one of) the other side(s) for a period of time. After returning to my original role I became much more effective.