Most importantly: even to the very last second, the patient's decision matters and is final. And procedure requires to iterate reminding patient's agency over and over again.
Having that moral debate out of the way, far more interesting is that euthanasia only ever has a place in a functioning healthcare system and social security system that puts the person's interests in the center. That is, by the time an elderly person do becomes eligible, it's never because they are a "burden" to their families or society.
In fact, it's extended to psychiatric patients as well. People with severe clinical mental illness can be eligible. Paradoxically, it's been observed that a sizable chunk of patients do have the paperwork, but actually don't go through with it. Just the mere thought that it's a non-controversial, accepted option which negates taking matters in your own hands is enough for them to keep going. Again, it's not a "get out of jail free" card. You do need to go through a lengthy procedure with many evaluations, and only after all other options are exhausted, before you become eligible.