[vegardx]

If you're worried about that you should be worried about what gets written to memory too. You have little control over where virtual memory ends up actually storing your bits and bytes. Unless you run without swap, but that's just a bad idea overall.

[ldng]

Lots of distributions precisely clean swap on boot or shutdown for security reasons. Also, clean a swap that is relatively small is faster than zeroing a full disk.

Your argument does not validate the use of easily recoverable .env file. Recovering a .env file is easier than recovering virtual memory.