for me and you, that is probably enough.

but you always need to know who or what is a potential threat to you. in the end it is just about making it enough of a pain for whoever might be interested in your data, so it is not worthwhile to them. having to break out forensic tools - just to get encrypted data, is probably painful enough for most. make them play puzzles with metal and glass shards will for sure open some wounds to pour salt on.

cremating disks is a thing for hacker collectives. termite is an extremely interesting thing to observe. but i am pretty sure there are more practical reasons, why people do that.