I can see that, but it also can become a control issue. I knew a guy who gave his wife an allowance, but it was for food and bills. She could never buy clothes or anything much for herself until he agreed to give her extra.
You don't have to have separate money or accounts to see that kind of control. When both people are working and making their own money, it takes some of that control away in that one person can't control all the finances.
The flip side of that is I know a guy whose wife works and all she is supposed to contribute is to pay the electric bill. He just found out it's 3 months overdue. She is always complaining she never has any money but she always has new clothes and knick knacks around the house.