You don't need a single core for a single task, things sleep and wait, "discord" or whatever low priority task can run together in the same core with other priority tasks. Just open up task manager and you'll see thousands of threads running, that's why multi threading (smt) even works - not everything is using the entire core or even using it all the time, somethings might be further along the chain, others in the middle, others just need a simple sum in the ALU, other are waiting for some other thing to happen first, etc.
Markting would have us believe "E cores are great for low priority things", well they aren't bad, but aren't great either, just a new marketing bulletpoint.
People want the best, regardless if they need it or not. If I can have 16 or 12 full fat P cores why would I choose to have 8 P + 4 E or 8 P + 8 E cores? Sometimes I might, but the simple 16 or 12 P cores sound better (I know I know, the 8P + 8E can outperform the 12P).
Well then the markting worked. Why would they bother with E cores after years of the "you don't need more cores" argument!? Lots of normal users need 16 cores, just depends on what you consider normal. If that wasn't the case, Intel wouldn't also be increasing the number of cores.
R23 is meant to represent 1 type of workload, that happens to be regarded as a good-ish way to measure saturated performance. I'm a software developer, R23 results don't really translate but I look at a high score as my code will compile faster. They're not everything, but better is better.