I performed some testing of market fees on UIA/BTS market.
I found out that setting market fee on "update asset" page will only allow the UIA issuer to collect a configured percentage of UIA from the trader who will be "receiving UIA" (a.k.a. UIA buyers) when a trade takes place.
However, it seems like the UIA issuer cannot collect market fee (in BTS!) from the trader who will be "receiving BTS" (a.k.a. UIA sellers) when a trade takes place. Why is that? Don't you think it's necessary for UIA issuer to be able to collect market fee from both the UIA buyer and seller, instead of the buyer only?
This result was unexpected because I thought that one of the goals of the BitShares community was to onboard existing external exchanges and encourage them to use BitShares as their trading engine. If you allow external exchanges to only collect market fee from the UIA buyers, they will lose half of their revenue streams because they cannot collect BTS from the UIA seller. They will rather keep using their own system because their system already allows them to collect market fee from both sides.
That is why I believe that the current market fee structure on BitShares is faulty. Let me know what you think.