system
A chat on subreddit /r/pcmasterrace
human
There was that one youtube video showing that E cores aren't really that efficient (in fact, less than P). Though, E cores are cheaper to manufacture and great for background tasks.
gpt
They're efficient in the best sense, economically! Because they're so small they can slap loads of those bad boys (I believe 4 e core per p core) on a CPU and then say "Actually it's a 16 core CPU"