Yes this was one of the questions I had about the contribution ranking system.
Ordinal value systems seem to simplify the process and may capture contributions that normally might not be recognized, but there are a couple issues:
How do the benefits of the ordinal system compare to a monetary ranked system as in your first example?
Austrian economists talk about ordinal rankings, but Mises talked about the benefits of the objective value of money in his Theory of Money and Credit (from what I remember). Money would alter each person's subjective ordinal rankings especially if the person did not immediately need to consume the good. Money may help coordinate the subjective rankings of each person in the economy as well as add a time-preference that allows people to compare ranking an item to be consumed today vs deferring it for another day.
Hence if Alice brings a steak, Bob brings candy and Sam gold instead of chicken. Both Alice and Bob may prefer gold if they don't want to consume any kind of food. Hence money can be an important element in any exchange process.An ordinal system may be too complex to understand compared to a direct money-based system.
In a money-based system, each person can claim a contribution amount based on their subjective opinion of how much value they contributed and use commonly used methods to measure (ie. $/hr or project-based fees)
For example:
Alice claims a $1000 contribution.
($500 for design package she usually charges clients + 10 hrs of time she normally charges $50/hr)
Bob claims $500
Sam claims $200
Then instead of ranking it's more about reaching consensus around the amounts that each feel they contributed. Each person can make their case about why he/she claims a certain amount, and ever other person enters his/her opinion about the $ value of the person's contribution and the average amount (excluding the contributor) can be awarded.
This monetary-based system may be more tedious, but it could lead to better precision and also a clearer understanding of the reward system that the consensus process fosters.
There are pros & cons with each system, but I think it's important enough of a difference that it may be good to have both options on the platform.