Thanks.  I thought there was some greater guarantee being implied (with later mentions of moon math). I see this doesn't actually prevent all ways of taking coins from others, and others have expressed the same possibility.  This is an area I'm trying to get a better understanding of, as I've been analyzing other algorithms, and I keep seeing these discussions pop up.

I still don't see what this solves that altcoin exchanges don't.  You have an entity that takes value into it's store and gives out value in an alternate blockchain that may or may not follow similar rules (some altcoin, maybe a Bitcoin clone or maybe something quite different).  The exchange can hold onto that value until the altcoin work is done and exchange back the value.  Validation is done in whatever currency is chosen for the transfer, which can obviously have any of a variety of zero-knowledge transaction and block validation schemes.

I've always expected altcoins are the natural transaction scaling mechanism, so I'm probably biasing myself, though.