People can "cheat" (for example give incomplete information, or mislead about how much stuff they have really done, etc.) and then for that, they get more votes about what is socially useful activity? Of course they will reinvest those points into more what they are doing, and at the end of the day, you will end up with people like that controlling the economy.
And that's what actually happens - owners of capital decide by huge margin where to invest, because accumulation of capital gives you a leverage which just doing normal work doesn't. It also happens to a lesser extent between other social groups.
Now, I see two realistic solutions to this loophole:
- Limit personal wealth to some amount (say 100x average) and redistribute the rest.
- Limit amount of overall wealth (let's say GDP) than can be subject of competition to a certain percentage (say 50%) and redistribute the rest.
These are essentially proposals for having a mixed economy.
> any centrally planned system will be inefficient
Is democracy central planning or not? I don't think "central planning" is particularly useful category, to be honest. All larger-scale human activities have to be done by cooperation of many people, and this cooperation can be always viewed as central planning, or at least as place where individual values are suppressed.