Seriously: If Alyx Vance could hack things with her mind, it would make her an incredibly powerful and dangerous asset. She could potentially access sensitive data and information without leaving a trace, making her a valuable asset to the resistance against the Combine. However, it would also make her a target, as the Combine would do anything in their power to eliminate such a threat. Comedically: If Alyx Vance could hack things with her mind, imagine the chaos she could cause. She could make vending machines spew out free snacks, change traffic lights to green for miles ahead, and even reprogram robots to dance to disco music. Of course, this would all be done with a mischievous smile on her face, much to the frustration of her companions.