Newer junglers playing the game don't understand why any of the wall of text mechanics on the previous jungle item work. It's easy to understand for people who've been playing for years, but it's a more intuitive metaphor for why things are happening for newer players.
Pet gives an understandable metaphor for why camps are getting damaged, why you get healed, why jgl gets bonuses from clearing camps and an understandable metaphor for why the unlocks happen when they do (evolution), catchup mechanics (pet is starving) rather than some arbitrary rules. For newer players, this is far easier to understand.
Plus it's just better fantasy and yeah the emotional support doesn't hurt 😊