There were a lot of legitimate uses for urine. It was used in tanning, for cleaning, for making gunpowder.

ancient rome enters the chat

They used to wash clothes down the river from burial ground because the lye mixed with human remains resulted in a natural soap leeching into the ground water/river

Allowing urine to settle and evaporate left behind ammonia, which is the main ingredient in many things. Among them, washing clothes, tanning hides, and some medicines.

So kinda.

The saying "Not even a pot to piss in." doesnt just mean you have nothing, it also refers to the fact you couldnt even make any money because if you had a pot you could sell your urine.