Yes. We live in reality and there are no perfectly efficient systems here. So, we have water towers and money.

The mistake is in thinking that the water tower is an essential part of the watering system. This is an important distinction to make because the goal should be reducing the reliance on the tower by increasing the efficiency of the irrigation system.

Same way we shouldn't fall so in love with a money that we think we need it to interact or that conducting a trade so efficiently that we don't need money is some sort of irrational or immoral act. It should be a goal. Anytime we fall back to money, we are seeing a point of inefficiency that we could try to solve.