I believe physician-assisted suicide (PAS) should be a legal option in any enlightened society for exactly the same same reason we euthanize our pets who suffer—compassion. It is the humane way for chronically suffering people to end their lives painlessly and with dignity.
I do advocate for a significant, patient-specific waiting period (>6-months) and the unanamous decision of a PAS team (patient, doctor, psycologist, and estate attorney). And, close family members should be notified and their feelings should be respected and factored in.
It would be soothing to just know PAS was an option in the event you or a loved one reaches a point of unrelenting pain and suffering. Hopefully its an option you won’t need to take. I believe PAS would actually result in a decreased suicide rate. Instead of rushing into suicide when you have the guts and means to do it, many may hold off, knowing they can choose the time to end their life and that it could be done even after becoming too incapacitated to do it by your own hand. Many may hold off and never follow through with the PAS.
How nice it would be for suffering people to say goodbye to friends and family properly (perhaps with a Celebration of Life) before ending their lives painlessly, instead of resorting to an illegal act which carries a negative stigma, can be botched and painful, and often traumatises loved ones and onlookers.
For me, I would choose PAS only after reaching a high level of chronic pain and suffering, a lack of joy, increased burdonsomness, and only after getting my affairs in order and saying goodbye to those I love.