Having read your most recent preferences.h article:
I’m curious what the value of using that location is vs. spiffs?
If your application needs security, is preferences.h a better location than spiffs?
Under what external circumstances would that file be over written?
The article Steve suggested gives you some more details:
“Preferences are stored in a section of the main flash memory with type as data and subtype as nvs. nvs stands for non−volatile storage. By default, 20 KB of space is reserved for preferences, so don’t try to store a lot of bulky data in preferences. Use SPIFFS for bulky data (SPIFFS has 1.5 MB of reserved space by default)”
As for the security issues, I don’t think one if better than the other. Someone correct me, if I’m wrong.
I think the preferences will be overwritten if you create a new namespace with the same name.