Cash Reserve is a measure of “real” money in the bank. Funds are how much you are planning to spend on different goals. You can increase the balances of Funds at any time by adding an income transaction or manually just changing the balance in a Fund but the Cash Reserve is tied to cash and can’t be “changed”.
For example, if you had save allocated $500 for birthday party and had $3,000 saved for vacation, you can easily transfer $100 from your vacation fund to the birthday fund. You could also just manually add a $100 more into your birthday fund without a corresponding bank transaction. In this way Funds are very flexible. But they also need to be tied back to real cash in the bank. So if you added $100 into a Fund without a matching income transaction, then your Savings would go down.
The best way to see if you have enough Cash to cover all your Fund spending is to look at your Savings. If your Savings number is positive, then you are good to go.