Having a trusted person(s) with the legal ability to make decisions for you if you are incapable is a smart idea.
Financial power of attorney (POA) is not the same as POA for healthcare. Acting on behalf of another person in the areas of property and financial management is beneficial for signing documents when you are unable to be present, withdrawing or making money decisions, acting on behalf of the incapacitated or absent person.
Ordinary POA ceases once a person loses mental capacity. Enduring POA is required to continue representation after mental incapacitation. Having control and naming this person is the importance of this formality while you are healthy and able to make decisions. Naming a POA is not equivalent to losing your rights. Many people specify that this assignation of powers happen only when a doctor certifies incapacity or other qualifying occurrences have come to pass and the exact actions the POA is allowed to take. You can revoke your POA choices at any time.
Spouses should have a POA document for each other. All legal and financial transactions are not covered by the mere fact of marriage.