Actually, I saw the development of the Recon Bike from beginning to end and there is a story with it.
When the Recon Bike model was made the original plan was for it to be a purchasable vehicle. I wasn't the person to make the final decision but I was involved with the discussion.
What happened was there was another issue being brought up. There was a discussion regarding early game vs. late game balance. A majority agreed that Nod had an early game while GDI had a late game with their mammoth tanks, especially when they hit elite or heroic. Nod doesn't have any vehicles that can counter mammoth effectively as they had low armor and low firepower to stand up against a mammoth tank.
So an idea was brought up with giving Nod a heavy tank to stand up against the mammoth. Remember, the Recon bike was recently made so giving Nod two new vehicles was viewed as a bad call. Not only would it help Nod's late game but it would help the early game as well. Therefore, we would essentially nerf GDI on both ends. Then to counteract the nerfs we would need to make another vehicle for GDI and cause a chain reaction of confusion with adding stuff to balance each other out. Then the Recon Bike is released as a crate vehicle.
Other arguments were made regarding how effective the bike will be. It would have been an early game unit. Combine it with buggies and you can dominate the field while the artys move in. Not only that but orcas will become worthless with Nod having a cheaper option to counter them. Also having more options doesn't mean its better. The game has vehicle limits and having more choices can cause more harm.
In summary, the Recon Bike was planned to be purchasable. It became a crate vehicle as a consequence of another balance issue being brought up. Then more thought went into balance before finalizing the decision.