This is so important. Too many asynchronous solution simply don't support cancellation, and instead just keep chugging along, doing undesirable things while wasting cpu & ram.
Apache web server also crashes safely when some PHP script leaks memory, but if you have a proper VM with GC this is something of the past.
Fortunately most web systems use Java or it's copy C# at this point and that is not going to change since Erlang has a simple memory model that cannot do joint parallel tasks.
Go has no VM, WASM has no GC, rust is too slow to compile... that leaves plain C with a C++ compiler but you don't want to have that on a server because assembly seg. faults.
So on the server you have to use Java. Not EE but SE.
What do you mean?
You cannot do atomic memory sharing between threads = threads cannot work on the same task at the "same" time efficiently.
Sometimes you can also reformulate the problem, but yes not all problems fit.
I would add though that whenever you want to write orchestration around that parallel work it's much easier in erlang than the alternatives.