That is another way to do. Or we can automatically figure out which models the subagents should be using for you. And update them as new models come out and the work your subagents do changes. More than one way to skin a cat.
This does make sense. I generally only switch between models in pi when creating a new session. And it is apparent from the promt if this just a "how to see open ports on linux" or "make a concrete plan for feature X"