An exceptional developer has done something exceptional. Authored a popular JavaScript library. Founded and grew a business. Lead the team that introduced a new product line that's now used at 5 million businesses. Authored the research paper that led to a new Photoshop feature. Launched an app at a hackathon that now has 30k users and here's the code.

These things speak for themselves. That's what makes them exceptional. These developers are not the norm but they're not diamonds either -- yet, still, they've already proved themselves and their accomplishments are enough that they can get a job without subjecting themselves to this obstacle course of an interview process.

Braintree doesn't really need exceptional developers to work on a 20th century credit card platform, it just needs competent ones that are socially compatible with its team.