You can either become permanently incapacitated or just temporarily unable to make important decisions. Having a power of attorney is important because you would want your loved ones to take care of your financial affairs when you are no longer in control of making any decisions.
A power of attorney is just a legal document that permits someone from your family to act on your behalf. If you do not have a power of attorney, then you would need a substitute decision-maker. The court requires a guardianship application in order to appoint a guardian. Mariana Samaan Law Firm can also help you with that.