I think that credit card debt is such a big problem for so many people that anything that chips away at it is a good thing.
The envelope system wouldn’t work for me, and it would never work for my husband. He never has cash. We have joint accounts, so any system we use has to work for both of us.
I’ve found having a weekly spending target helps me manage our spending. I don’t worry about how much I’ve spent down to the penny, but I do have different targets for each week. For instance, we don’t eat out during weeks that we have a lot of money going out for the mortgage or other payments. I’ve also gotten better at planning for annual expenses – association fees, car registration, etc. That helps me manage the cash flow to avoid debts without having to count expenses down to the pennies.