I would favour a gentle going into the good night as a function of age, to eliminate the possibility of immortal nodes.
I’m wary of trying to reason the justification for this because I think it is something we don’t really understand and will find it hard to model - in both cases because humans are generally good at situational and short term thinking, but not so good at thinking about time, particularly when it comes to long term stuff. In part because it is a hard problem, and in part because we all die and don’t get much practice at thinking over time spans longer than our own span of capability.
The above is my main reason for supporting such a mechanism: I look to nature, and everywhere I see it taking the wise, the stupid, the best and the worst of every individual, in every species, and turning them to dust, partly at random but inevitably after a pretty clear cut off period. I don’t think humans understand why, or the consequences of changing this for the reasons already cited.
I trust what I see as nature’s wisdom more than any argument I could make. I will just say that I can see node mortality might well be a way of eliminating over centralisation with all the dangers that brings.
By analogy, I suggest that humans have been stretching the boundaries nature’s scheme by having achieved a kind of cultural immortality which has allowed us to over centralise the earth’s ecosystem, and right now that’s looking like a failure of nature - at least of evolution, which it will correct in the usual way: collapse and start again. Still, better to avoid that if we can, including with SAFEnetwork 
In fact, SAFEnetwork is one of the things which might help us avoid this larger threat.