Characters can have a lasting effect on the viewer if their death is shown.
If they end up surviving what seemed impossible (like Pell), it actually worsens my opinion of them. Like, what are you doing here? You just sacrificed yourself by carrying a bomb into the sky, had it go off, and you’re fine?! How?!
I‘m not really happy or sad when it happens, but instead confused and irritated.
What’s even worse is when Oda does absolutely nothing with them afterward. They just exist to exist, only to be seen in cover pages once in a while.
I want these memorable moments to still hold significance, I don’t want them to come back if Oda’s only going to use them as a convenient plot device and abandon them. It’d be like a fate worse than death.
If Oda were to bring Monet back, or any character for that matter, I would hope it’s for a good reason.