Why are investment accounts typically not on-budget?

In Roo, the sum of all on-budget account balances always equals the sum of all pouch balances. If an investment account were on-budget, market fluctuations would directly affect your pouch balances — a bad week in the market could shrink your Living pouch even though you didn’t spend a dime, and a good week could inflate it with money you can’t actually spend. This breaks the behavioral feedback loop that makes pouches useful. Instead, investment accounts are tracked off-budget, where they still contribute to your net worth without disrupting your day-to-day budget.