To distinguish: Everybody has a reputation and that's normal, ethical, and fine. If a restaurant serves you shit food, and the waiters fart in your face, you spread the word to others, and possibly leave a review on yelp. That's 100% fair and ethical.
However, reputation systems track that sort of review across all aspects of their lives. And add in algorithms or a set of ethics demanded by the state, and you have an invasive system that cross-references you at every aspect of your life and turns every citizen into a snitch, that are encouraged to snitch on each other.
Now that's just social credits. Reputation in the sense that it replaces all currency is just effectively centrally planned socialism. It encourages corruption and shmoozing.
It means generally some 'reputable' council decides if you deserve a restaurant or not. So by bribing them with whatever (and there will always be bribes), becomes the only way of accessing resources.
In a very real way, the Soviet Union was a status/reputation-based economy. Some 'reputable' people decided all aspects of your life, and since you couldn't put in extra effort or balance your capital in an official manner, you did bribes in an unofficial manner.
Has anybody seen the Soviet film 'Garage'? It goes very much into how such a system works. How something as basic as making a garage for a bunch of scientists becomes a nightmare with people turning on each other in the process, and how everybody really is the victim in such a system.
Maybe in the modern-day, it would be a bit different because the most popular influencers are a bunch of tools. And that's why Rhedyn brought up the requirement of squashing free speech and 'proper education' so that the influencers would be what the state needed to be.
Star Treks' economics are just hand-waved and just assume that what the fundamental change is in the average PERSON. The idea is that it's not so much that a system made people better, but better people made a better system regardless of underpinnings. When it got all anti-money that was just stupidity on the writer's parts. It's like an idea that not having toilets will make people poop less. 'We have outgrown the need for toilets so we don't have them anymore.
Because human greed is limitless, no matter the replicators and near infinite energy. Some credit systems would have to be implemented for access and special privileges.