Memes

One thing to consider, assuming the red one is mental time travel (which is the only way it'd really be at all useful), you're essentially murdering everyone who exists from your subjective present to the jump point to replace with at best very similar clones and possibly no one or completely different people. Then you have to also assume the timeline isn't fixed and you can actually change things, and thus contend with butterfly effect causing divergence making your knowledge less useful. Sure, little changes probably won't impact things on a global scale for a while, but once you start doing big things like investing or preventing terrorist attacks or something that could cause major divergence. Ethically any kind of useful time travel should be limited to "World is already wiped out" scale scenarios where the alternative is worse.