So, we have Crystals > Boss items but we do not have the reverse of Boss item > Crystals.

It would be nice to have the latter for those of us whom are crazy enough to farm out for Eurekan Armour which requires an obscene amount of Crystals and thus will likely end up obtaining bunches of Boss items from following Trains which are useless outside of upgrading weapons.

Ideally for Anemos, they'd be exchanged for Anemos Crystals instead of Protean to help with the final stage of the Armour there.