Financial openness in partnerships is good. Money does not necessarily build a home but easily breaks it. Some people profess love, but that love does not stretch to their money. The advantage of running a joint account is you can share responsibilities more easily.
To an extent, it’s a good but it’s not everyone who is sensible with money. Some marriages broke down or a spouse passed on before they realised the debt they’ve run up on ‘their’ joint account. Keep in mind that you’re each responsible for all the debts that either of you run up on a joint account. It works for some people who are disciplined and knows how to manage
There are some people you can’t trust with money. You ‘rely’ on them to manage your finances and they squander the money. Their integrity level moneywise is zero. People who cannot take care of their own business cannot take care of other people’s own. Someone who is not disciplined with his/her own money is not a person I’ll run a joint account with because they won’t be able to account for monies which grew wings.