I think double-entry bookkeeping is, at least to me, as fundamental to economics (and of course business) as logic to math. Even if some actors don't use it explicitly, it still holds. If I buy ten apples for 10 bucks, I have ten more apples in stock and ten bucks less.
Many economic discussions (not only on HN) get out of hands because people don't try to see the full picture or deliberately choose to see one side. I've even seen a professor of economics claim in public that the world is too much in debt. Well, double-entry bookkeeping tells you that there are always two sides to consider.
For example, in case of governmental debt they ignore the other side of that debt, which might be assets. Assets like airports, schools, bridges, etc. Usually, we call such things useful.
Another typical example is the central bank "prints money". Well, double-entry bookkeeping tells us that it's not possible. If they hand out currency, the counterpart needs to trade something in (typically repurchase agreements with commercial banks). (Leaving aside here the idea of helicopter money, which could even go into neg. equity or a loss.)