There will be shortcodes in the future to display coin rates.
The coin that exchange rates are given against is indicated by walletsUserData.fiatSymbol. This is normally the selection under Wallets > Exchange rates > Default fiat currency but can be overridden in a user’s profile.
The exchange rate for e.g. Litecoin is accessible as wp.wallets.viewModels.wallets.coins()['LTC'].rate.
Hope this helps. Once the shortcodes are ready I will report it and there will also be a blog announcement.