At least in Illinois...(as a previous poster wrote, every state is different)
Account is titled:
Single owner, no beneficiaries - If you are incapacitated, the banker says to your representitive, "I'm sorry, we need a court order". If you pass away, again it's "I'm sorry, you need a court order" You show me a copy of the will, amd I say, that's a very noce will. I need a court order. (Court orers almost always require an attorney, at least in Cook County)
Single Owner with beneficiary - Incapacitation - "I'm sorry - court order". If you pass away, we ask the beneficiary for a copy of the death certificate and ask how he or she would like the money.
Power of Attorney - great during the life time of the account holder, but ceases upon death.
Living trust - Incapacitation will either require that you (the grantor) resign as trustee or a doctor certify that you are incapacitated. Then the successor trustee takes over. At death, it's the same thing. Prove the death (with a death certificate) and the account is then handled by the sucessor trustee. No court orders needed
While this may not help with your decision, it may help when you know how the bank "thinks". Each person has a different need and each financial situation is unique.
Good Luck