(author here)

1. Thanks for your remarks on memory efficiency. I wrote that piece a few months ago, I'll have to reread it, but if I implied something wrong, I'll try and amend it!

2. Regarding "multi-threading risks", I don't think I claim that. I have definitely encountered race conditions in single-threaded async code. You don't encounter the same kind of memory corruptions as in, say, multi-threaded C, but you can definitely break invariants on data structures. If I miswrote/wrote something unclear, I'll need to fix that, too!