Backing up wallets are important, but regarding lost coins in general on the Bitcoin blockchain, I tend to agree with Satoshi.
Lost coins only make everyone else's coins worth slightly more. Think of it as a donation to everyone.
I am not surprised at the mixed response to Popescu's demise. He was an amazingly prolific probable genius, and he was an (in my opinion) awful person.
I would be extremely surprised if the mass of his coins, however many there were, were not set up in a fairly tight system. I think there is a VERY good chance they are lost as in a donation to us all ala Satoshi. And in this case the size of the donation could be ridiculous... as much as 5-7% of the remaining float, maybe even more.
Of course no one knows (yet) how many there really were, and like the satoshi coins we most likely will never be able to know for SURE that some sex-slave who got close enough to figure out his system would not be able to access them and rock the markets, lol. Seriously it's a possible time bomb the size of the Satoshi stash itself.
He was so twistedly brilliant I would also not be surprised if he set them in some convoluted dead man switch setup. He could surprise us from the grave.
Assuming he is dead at all.
The intrigue in our little world runs deep!
Does anyone know yet what killed him?