The betting stuff enables what Vitalik refers to as "dark uncles" or "dunkles", which Vitalik incorrectly thinks will solve the nothing-at-stake problem.

Also Casper has the problem that all deterministic finality PoS and Byzatine agreement systems have, which is a 33% liveness threshold which if that many validators balk or stop processing, then the chain can't move forward without a hard fork.

The only way to replace PoW is with an Inverse Commons consensus protocol, which is my new invention.