Squirrels don't really hoard in the sense trillionaires do ("gathering a great quantity for one's own private collection"), they take seeds and bury them all over the place, which is meaning #2 in the dictionary ("save in one's mind for a future need or use"). The squirrel and other animals eat them later, the 50+% nobody finds to eat can take root. That way, squirrels play an important role in seed dispersal for many species of tree.

I suppose the trillionaire analogy would be they themselves investing money.

And over the long term it compounds to more food for their descendants through the buy and forget investments (the trees that sprout out of the stashes).