I find it crazy that this isn't a feature. Almost 100% of users will have cash laying around in a bank account and without being able to add it, you're unable to see your net worth. There is the "available cash" feature but it's not workable, you constantly have to figure out what you had in there last time and either add and deduct to get to your current state.

My suggestion is to simply allow creation of an "financial account" and assign a value to it in a particular currency (negative values should also be accepted to track debt). Extra bonus would be if you could also assign an interest rate to it, which would be useful for a huge amount of people who have money in an interest bearing account. This way if you had bank accounts or credit cards, you could just add three "financial accounts", give them the label of the bank/credit card name and be done. The total value could be updated periodically and manually (except with the interest feature which could be done automatically)

I think valuable especially when holding cash in different currencies