The big advantage of cash envelopes is that, if you budget properly, you will always have the cash to pay a bill when it comes due. No more worrying about where the money will come from, be it for mortgage or rent, utilities, car payments, repairs, taxes, discretionary spending, etc.
The most common budgeting method used is a blank piece of paper. We've all tried it at one time or another. Income is listed on one side, expenses on the other. The idea is to balance income against expenses so that, hopefully, there is still some money left at the end of the month. _ There are at least a couple major problems with this method. First, it's pretty easy to overlook quite a few expenses. Things like that daily stop at the coffee shop, or the cost of a car registration that happens only once a year.