Gem allows adding more fields to your expenses, so you can record and organize expenses into wallets, events, tags and more.
These "fields" behave like a group of options (similar to wallets), which you can choose from when recording expenses, when searching, or creating budgets.
Since your field name is something like "Wallets", Gem will refer to it as "Set wallets" and "Create a new wallet". If you find this funny:
If you add most of your expenses to a single wallet, like a primary credit card or budget, Gem can automatically choose this wallet for you whenever you create new expenses.