If not trade, at least a way to recycle a number of repeated parts for something else of the same capsule or more tries, just like in other gacha games.
Trade at times gets tedious and tiring because of people over or under valuing stuff, since there is no way to have a fixed value on items. In surge at the end they kinda had a good system where you could buy someone else's stuff with RT but at the same time no one wanted "common" RT for their rares.
There is also the black market of people buying stuff with real money on the side and getting scammed lol