Currently the phoenix credits are becoming more and more useless since the 191+GS drops from incursion and are much easier to obtian (i can get 600-800 in two days farming dz5/6) so as the title says having the option to reroll 2nd attribute with phoenix credits would create usefull sink for them (i wouldnt mind if it was hefty price like 150 credits 1st try 300 2nd and so on).