I partly agree with your opinion. But on your own perspective, you are concluding on a general perspective of a bounty hunter and not considering the client. These bounty hunting platforms mentioned above are not only focusing on the distribution of tokens to the participants, they also focus on the service to their clients. I am judging a bounty hunting platform base on the 2. The service to their client and service to their hunters.
These mentioned above are good platforms for their clients, but totally I am not satisfied with their distribution of tokens to their hunter. They don't even have a spreadsheet where we can see the data on the distribution of the tokens. That's the lacking feature of these platforms I think. Amazix, on the other hand, is a very good management firm, the problem is that, as of now, they don't have an intuitive website where hunters can participate their bounties easily.