Answer: David can help us create use cases that lock Tez by providing game theory insights. For example, he can help us identify the most effective strategies to incentivize users to lock their Tez, such as offering rewards for locking Tez, setting up a leaderboard system with rewards for the top holders, or using a loyalty program. He can also help us analyze the impact of different strategies on the overall network security, as well as the potential risks associated with locking Tez. With his help, we can create a comprehensive use case that will help us maximize the security of our network.