If you don't have advertising cookies set then you're either a robot or a potentially unprofitable human user from Google's point of view. Both would be best avoided.
As others have noted here, that's not the goal here and the captcha will degrade to the current ones in this case, but it highlights an interesting way for internet properties to maximize their revenue per user by only allowing users whose existing advertising footprint suggests they will contribute meaningful value to use the service in the first place.
Detecting bots is the first step to this, but detecting potentially unprofitable humans would be a natural extension.
As others have noted here, that's not the goal here and the captcha will degrade to the current ones in this case, but it highlights an interesting way for internet properties to maximize their revenue per user by only allowing users whose existing advertising footprint suggests they will contribute meaningful value to use the service in the first place.
Detecting bots is the first step to this, but detecting potentially unprofitable humans would be a natural extension.