Keeping your bag, carry-all or "man purse" is an important part of keeping yourself organized. It doesnt matter what you carry or what you call it. All of us need something to carry important papers, supplies and personal items in when were on the go.
I spoke with someone recently who said since he started carrying a man purse he is more prepared when he is on field assignments because he has convenient access to the items and tools he needs to do his job more effectively. He can carry a pad of paper and pens in it, for example (a convenience a traditional wallet cannot accommodate).
Having what you need at your fingertips is critical when you are mobile. Whatever you carry, keep it clutter-free and organized. Its a time-waster to have to search for items you need and it can be embarrassing when others (think clients, airport security, etc.) see your overstuffed and disorganized bag. Carrying too much can cause back and shoulder pain. It can also be a sign that you need to work on your time management. Throwing tasks into your bag just in case means you may not be scheduling time to get them done.