Effect only triggers when destroyed by card effect (not battle).  But with weak stats, its likely to be destroyed in battle.  There are ways to destroy via card effect; if destroyed from the deck, it can be a +1, however destroyed in the hand it doesn't generate advantage.  The attacking restriction is sensible in some cases but is a tad draconian.
 
1.5/5​

Hello Pojo Fans,
 
Petiteranodon is a pint-sized cutie for the resurgence of the Dinosaur archetype.
 
Any card effect that would destroyPetiteranodon and send it to the grave gets you a a free Special Summon of a Level 4 or lower Dino, though it can't attack. Petiteranodon is one of your two main searchers in the deck, teaming up with True Kings to swarm the field with high ATK monsters while maintaining resources. The two best search targets are Souleating Oviraptor and Miscellaneousaurus. These monsters can also be used alongside the True Kings as well to gain even more advantage. You can also use Petiteranodon as material for a Synchro. As a Level 2, Petiteranodon can grant you a wide range of Synchro options. Once it's done using its effect for True Kings or another card effect, you can banish it with Ultimate Conductor Tyranno, the beatstick of the deck.
 
In combination with the right cards (and there are many) Petiteranodon can create quick advantage on the field of the player without using their Normal Summon.
 
Advanced-3.5/5
Art-4/5
 
Until Next Time
KingofLullaby