As we know in the Déjà Vu ep Jackie almost choose to send Jade back to avoid the mishap she tends to bring until he relizes she saved more then he could count
What this shows that had he gone through with that plan he would’ve ruined the time stream and alter all the good he and made to protecting the world from the forces of evil as quoted by clockwork changing the past can have dire consequences even if you have the knowledge of the future and also more importantly, changing the past must always be last resort never used all the time
Not saying, Jackie would do this all the time I’m saying sending his niece Jade back would have had dire consequences. For example, the dark hand would’ve gotten the talismans and. Shendu would’ve returned and nothing would’ve stopped him, proving that Jackie unknowingly would have doomed the world because the timeline that he and Jade hail from didn’t need correcting at all.