Trade Moments with other Collectors
This feature would enable people to propose a trade with another collector. You'd select a moment you like of someone else's, select "propose an offer", and select moment(s) to offer. The other person would be notified, and they could reject or accept the offer. I would also add an option for people that aren't interested in trades a way to opt out of this feature (like in their profile, a checkbox opting in or out of trade offers) so that nobody gets spammed with requests if they're not interested.
I believe that it would make moments feel like trading cards in the physical sense, where people traded cards with each other often.
And, perhaps this could also be incorporated with trade tickets. For example, if the person you want to trade with accepts your offer, the person who initiated the trade is deducted one trade ticket. That way, it is also encouraging people to trade in moments for trade tickets, giving trade tickets multiple functionality. I've added an image as example UI.