Further down in the description, "....pilot enters a two-year tenure period as a paid instructor...."
Maybe not a catch, but that's where the payback comes from. Depending on details, it might be a great way for somebody to get started, and, as far as I know, Flight Safety Academy is a reputable organization.. Myself, I'm always reluctant to contemplate signing any contracts for indentured servitude, but that's just an opinion.
Potential indentured servitude crossed my mind too. But, as long as the person who took the "free" CFI tics is paid the same as a person who walked in with them already...and was going to instruct for two years anyway to get some flight time...
If the "free" recipient were to be paid less for getting the "free" ones, that'd be a deal breaker.