How does this work in detail? We donate TRE to a charity organisation but the charity will have to sell the token to BTC and fiat most likely. then we cannot trace all the steps anymore.
Thats one of the cases. But think about the following:
You list item in favor of Orphanage Org. When item is sold the TRE goes to them. What ere they gonna do with the TRE? One of the paths is as you said to sell the tokens to BTC and then to fiat. But why they need fiat ? To buy something, right. Now think about what will happen if the items they are willing to buy are available on TRESARO marketplace but are listed in favor of for example Cancer Org. If Orphanage Org buys the item the TRE will go to Cancer Org - for the first time in the world one charity org is actualy donating to other charity org. And what will happen when Cancer Org buys something from TRESARO marketplace listed in favor of some other charity...
We belive that this is very big driver charity orgs to buy from TRESARO and not look outside. Usually charities are competing for a single pool of resources (donations). The Tresaro market implicitly turns this competition into cooperation.