You have a great view about this topic... having a joint account for a purpose is nice and I also agree with you that each partner can contribute to a family need without necessarily having a joint account
In my home for instance, hubby and I had joint account when we planned on buying a car. Now we were so deliberate with contributing money to achieve the purpose..hubby was putting 60% and I , 40% and it was handled well...since then we continued for family expenses
Really this is a two sided case depending on the couples involved