I was in Illinois over the weekend and read about this. On one hand it’s pretty interesting. My take on the word “potential” was this. The gar may or may not take. The gar may or may not really eat the carp but that’s the idea.
There’s no way that gar will solve the problem though. Even if they thrive and have an appetite for the carp then I predict a predator/prey relationship. Meaning they will eventually strike a balance where the carp are reduced but not eliminated.
Other than looking extremely scary I don’t know what hazards a gar poses to people or fisheries.