When Hospitalised, there is always a possibility of undesired events that can happen. What if..
When one is incapacitated, they would not be able to decide and do a lot of daily basic things and access to their assets would de difficult. We would need to ensure that there is someone you can trust to handle all your affairs for you. Once you decide who it should be, it makes it easier for your loved ones to go to the courts to get a power of attorney for you. This enables them to access your assets to pay your bills and so on. They can also decide for your on your behalf.
Save your loved ones the difficult decision on whether to continue life-support for you or not. It is your life, after all. Let them know of your wish and reassure them that it is the best decision for all parties.