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The feature only notifies you when topics (you posted on) get nuked, not when your posts get specifically deleted by mods (you already get a PM for those, as you already know).
Ohh, am sorry for misinterpreting the context. Well, wouldn't it be better if we got notifications for posts getting deleted too ?
Though we get a PM, we could easily access the notification when we are not on the forum

I think this notifier was meant to make up for forum's missing functionality regarding mentions/quotes.
Regarding your suggestion, we already receive pm (and email when you receive pm), so I personally don't see any need for it and if done it would be wasteful work.