Not saying all the finances should be merged. It can be a middleground, combining the minimum to cover the necessary monthly bills. If partners have issue with that, are we saying there's 0 trust in relationship.
My spouse and I were cautious combining finances at first. We started at bare minimum, just enough to pay electrical bill. Over the time, we combined a sizable portions of our incomes to cover necessities and save for the future.
It's definitely a matter of opinion, not saying what's right or wrong. It just makes sense logistically to us.
For example, if there's no shared bank account, who's receiving tax refund from IRS? 😃
And who's paying for house renovation? Shifting funds using Venmo / Zelle all the time is very inconvenient IMO.
Again, only my opinion.
OP has other good evidence.