The Urbit community hosts many IRL events and, inevitably, this means splitting tabs with other Urbiters. Urbit needs its own expense sharing app that seamlessly keeps track of all expenses and IOUs in one place and works with both crypto and fiat.
The Urbit version can be loosely modeled on the expense sharing app Splitwise. Splitwise uses centralized cloud infrastructure, but an Urbit version could be architected so that accounts payable and receivable are kept on your ship. The Urbit version should also be mobile-first, so it's easy to use on the go.