...with 17,000 BTC.

(Valued at 220k USD then, or 700M USD today)

Well the bitcoin supply is limited, so it's quite a big loss.

For them! Due to the way the economy works, destroying money is actually a donation to everyone else who has money (deflation).

Still hard to imagine this wasnt ever just laughed out the room immediately

It's infinitely divisible, so not in the same sense as the loss of any other limited item. There could be only one Bitcoin in existence and it wouldn't change the utility of the system.

How do you send half a sataoshi?

Get all the verifier nodes to agree to increase the divisibility of BTC into sub-satoshi (e.g. via a BIP request approval). This will not be necessary for many generations.