Blurr gets to know the members of the Earth team in person. He finds out that they too were misfits on Cybertron, bullied, rejected or neglected by their own. He sympathizes with them and tries to plan things out in a way that will leave them unharmed.
Also, the in the Allspark Almanac Blurr says that Longarm sent him to Earth to keep an eye out on the Earth team. This obviously was so that Shockwave could be aware of what they were up to and whether they caught his trail. In this AU, with Blurr not captured by that racer human + willingly spilling out as much info as possible to Longarm, Shockwave would've been able coordinate with the Decepticons much better. Plus, Blurr could feed Optimus' team some disinformation if needed.
[Part 23] "Earth Team" (Click here for other parts)