Certainly.

And when you want to buy a ship, the shipwright or the pilot would be better?

True.

Then what is that joint use of silver or gold in which the just man is to be preferred?

When you want a deposit to be kept safely.

You mean when money is not wanted, but allowed to lie?

Precisely.

That is to say, justice is useful when money is useless?

That is the inference.

And when you want to keep a pruning-hook safe, then justice is useful to the individual and to the state; but when you want to use it, then the art of the vine-dresser?