I never said that it was about "permission" I am saying that as grown adults, we don't want to "mention" to the other spouse about every little purchase. That would drive us bonkers. Things like new shoes, are a normal life expense and I would just buy them if I needed them. I don't need to have my husband affirm my decision to buy something. If we have the money, I am going to buy what I want. My husband doesn't even want to hear about that kind of minor stuff. If we ended up talking about every little purchase, that would consume our lives. I don't want to hear that hubby bought a can of soda at work every day. This might be a generational thing, but I don't feel that any adult should have to discuss every minor purchase with their spouse. No one is talking about the big purchases, but the everyday ones, every adult should know their budget and what they can afford without having to have the other adult in the house in on it.
And that is where the separate accounts come in. You can have access to money that you can spend on whatever you want without it being taken out of the household accounts. You wouldn't need to "inform" your husband of every little purchase if you are just using your discretionary money.