There could still be runs on banks. If everyone takes their money out of banks, the money supply would collapse to 10x smaller. If you believed this was in the process of happening (rumors of a coming war, etc.), you'd want your money out as soon as possible, whether it had to be 6 months or 6 days, you'd still want out.
> you need to break your time deposit for an emergency? Nope, can't do it
But you can. Just take a short sell on the asset.
> Strikingly, economists thought about these things before Hacker News.
That's a little snide. Economists discussed exactly what I just wrote 100 years ago.
I'm not saying this design doesn't have tradeoffs, but it's laughable to suggest that our current banking system is anywhere close to perfect.