Why do I need a trust if I have a will and durable power of attorney and power of attorney for health care?
I don't know about "needing" a trust. However, if property is in your name at the time of death, the property could not be transferred to the beneficiary unless you go through probate. A trust has the property transfer without going through probate, thereby making things more efficient and easier and saving money.
You likely dont, unless you are in a high asset bracket.