When casting Goodberry spell with a Component Pouch it is assumed that the pouch has a sprig of mistletoe to be used in the spellcasting as the material component.
Can a druid simply take this sprig of mistletoe and use it as a Druidic Focus?
The issue is about the decision making for starter equipment, if the pouch already includes a Druidic Focus you can take that out and use. Why even start with a different focus.
What good would it do?
One thing I came up with is a sprig of mistletoe is easier to hide in a pinch and even easier to camouflage as harmless in case of a pat down.
I know the Druid could simply start with a Focus anyways, but saying if they started with a pouch and then changed their mind. Maybe even use the pouch mainly after removing the mistletoe. Potentially making 'smart' enemies trying to get the pouch away from you just to grab the mistletoe and go on like nothing changed.
If you need an 'in-game' situation:
Druid loses his focus. Party Wizard gives his Component Pouch to the Druid and the Druid grabs the sprig of mistletoe since he can cast Goodberry with a Component Pouch. Most sensible way to continue is to note the pouch is missing a sprig of mistletoe and move on, Wizard can't cast any spells that require sprig of mistletoe as a material component, Druid gets a free focus.