First of all, it's very unlikely that at that stage in someone's illness they're able to communicate with me, but I very often hear from family members along the lines of “Can we speed this up? It's torture for us watching this go on and drag out.”
For many patients, when we withdraw technology, they die quite quickly. For others, they can linger for hours, for days, sometimes for weeks, but the outcome is certain. This can be very distressing for families, and occasionally it can be uncomfortable for patients.
For patients who require technology to have a shot at life, but for whom that technology then fails, there is certainly a role for assisted dying.