Some employees do one thing really well. Some do a lot of things well. There is a certain thought process in the market that if you are a multi-tasker, you can’t be the best in the world at any one thing. But there’s also something to the idea that you can be the best in the world at working for a company that needs a lot of things done well.
It may not be a great strategy if you want to climb corporate ladders. I think the specialists are more apt to achieve those ends. Still, if you want to grow with one company (likely a smaller company), making yourself needed and valuable can be achieved easily by doing a lot of things well. In fact, I’d argue that small businesses thrive due to a few select individuals who outperform on a bevy of tasks.
“Big Iron” companies aren’t looking for that. They have specified roles. Attempting to go above and beyond can be construed as stepping on other peoples’ toes for personal gain. It’s all very contextual. Peep the context.