The idea of death can be a relief while we're still alive. If death didn't exist. If we all lived forever, we'd know there was no end to the pain. Still, if that's all there ever was, I suppose we wouldn't think to question it. But yeah- passive ideation can be a comforting thought.
The actual thing though. Who knows? Personally, I doubt we'll feel anything after death. But, if there are afterlives then- it's going to depend if we go somewhere better or worse I imagine and how conscious we still are.
We can't entirely predict how we'll be feeling right before death too. Probably depends on how we die. Sadly, I think a lot of suicide methods involve large elements of fear, discomfort and pain. May as well 'enjoy' the idea of being relieved by death while we're still alive I suppose.
I remember a more pro-life member once making a kind of bizarre argument like that once. Like- if you get any enjoyment out of life- even if that enjoyment comes from thinking about your own death/ non existence- you still need to remain alive in order to be able to experience that. Of course, it seems kind of ridiculous to me because, hand in hand with that idealised idea of death is the knowedge that it's going to be incredibly risky and very possibly painful and terrifying to actually accomplish. It's actually a horrible longing rather than some pleasant day dream when it comes down to it- active ideation for a lot of us. It would be nice to think that after all that, we would actually be 'rewarded' with a calm, peaceful transition but, I doubt it for many of us.
Really, even in an ideal scenario- assisted suicide in a clinic. 100% guaranteed death and hopefully, relatively painless. Would it still be an entirely calm process? None of us know what death actually is. We may have someone we care about with us who we're having to say goodbye to. We may well be feeling bad for them. Plus, we're about to drink a poison. I imagine it's a lot like going in for an operation. You hope it will work but, you're full of uncertainty. I'm not even sure natural death is always calm either. Again, it probably depends on the circumstances.