In practice it is always going to be abused by the ruling class under capitalism for eugenicist purposes and as a way to get out of having to provide expensive healthcare to those who need it. Far cheaper to psychologically manipulate vulnerable people into "consenting" to being killed.
Something like this can only be ethical under socialism where no one lacks healthcare or the material means to live a comfortable life.
I am especially opposed to it in northern Europe which is exceptionally racist and eugenicist even by the standards of Western societies.