1. Early game jack of trades: If you're lucky enough to find a high level you'll have a decent early game mount, iguanodon is basically just a better Parasaur aside from the paras ability to detect danger.
2. Travel mount: Iguanodon is very fast and literally has infinite stamina.
3. Taming mount: You can also use weapons while riding it, and it jumps fairly high.
Iguanadons are super slept on for their utility outside of making seeds. They hardly consume stamina when running on all fours, you can use your hotbar while riding them, and they're forever giving you moral support with their permanently fixed thumbs up 👍
Iguanodon is a very useful dino. Its strong, fast, have a lot of stamina, can jump really high, can collect a ton of berries, can turn it to seeds, when u need, and poop for u big eggs. :D A must-have creature in the game.