There were a few reasons! For one, both of our previous collaborations (kekis and I) have featured humanoid protagonists with four regular limbs. We initially discussed having some kind of robot on wheels be the main character, not only to spice things up but also because the walk cycle would be easier and faster to animate fluidly (you may notice it really only has 8 pixels go in circles on the scooter's wheels, and the rider slightly shifts forward and backward). We were also discussing a sprint function, which would be equally easy to animate if no legs were involved.
When we started thinking more about our character's backstory and how they're stealing someone else's property, we realized we should make him as douchey as possible and make him ride an e-scooter (our native country has a stereotype of e-scooter users being annoying in cities). That ultimately developed into the Paavo we all know and love today: a microwave pizza-loving, government property-stealing e-scooter enthusiast.