Thank you for your feedback!
We admit that we didn't have enough time or much thought put into it! The way it was supposed to work was that if you hard stomp many tinies or a special tinies (but it was one), you would grow much bigger than your regular stomps. But as you can probably tell, it wasn't that impactful or enough to be considered that useful.
So we are considering giving some love to our tiny vehicles to have some gameplay elements rather than simply existing there for visual effects.
This is why we wanted to have an Open Playtest to gather your thoughts and ideas!