As a swapper, I always want to give those coins to the opposite person which are of his interest.
Once both members select coins from swaplists, there is no way to know what are the top priority coins for opposite person from his/ her selection. There could be few coins which the user may want badly from all those selected. I am calling these as 'Priority' coins.
A priority flag would help address this requirement. Both swappers can help each other by doing their best by providing more or all coins flagged as 'Priority'. One may flag or unflag priority coins at any point of time during the 'Discussion' phase.
I am sure many Numista members here would have felt the need for such a feature which is missing currently.