If you are perfectly prepared for your passing and made your will, arranged all the financial stuffs, told your friends and family everything needed etc. then y

If you are perfectly prepared for your passing and made your will, arranged all the financial stuffs, told your friends and family everything needed etc. then you don't need to give access to your accounts. But many people don't have that luxury. When death is unexpected, things get messy, e.g you may want to continue paying the mortgage on time, or shutdown social media accounts, or make announcement of their passing using those accounts, or contact their lawyer, or cancel subscribed services, and so on.