So if a POS chain has the ability to leverage POW/Bitcoin security, isn't that a huge advantage? Now PoS becomes more secure.
Sure, but the question still remains. Why do you need to launch a PoS chain if, in the end, you need to rely on another chain to make sure your transactions are not reversible? You can simply launch a decentralized database without any crypto at all and then chain the hash to Bitcoin or something similar. While I do agree that fast transactions can be beneficial if you want to use them for payment activities, from a security perspective this means the chain by nature is unreliable since the beginning. At the very least, the proposal for this project that you shared is not that convincing as far as I can understand it. That being said, I can understand why some people like the idea of relying on Bitcoin when they can launch other coins and use PoS to get faster transactions. As long as they can make sure the attack does not happen before the timestamping on the BTC network is done, it might work for their purpose. The next question would then be how reliable it is. CMIIW.
