John Hancock, one of the largest North American life insurers, will only sell policies that include the tracking of fitness and health data through wearable devices and smartphones, the company said on Wednesday.

The details: The company's underwriting process will still exist, but all policies will include the wellness program, called Vitality. Policyholders will be rewarded with discounts on their premiums and gift cards to popular stores when they achieve goals in a points system.

Why it matters: "The John Hancock move is a rare sighting of advantageous selection in the insurance industry, which normally struggles with its opposite, adverse selection," writes Axios' Felix Salmon. "With advantageous selection, the kind of people who sign up for fitness-based interactive policies tend to be fitter and live longer, which are attributes life insurers love."

The details: Hancock's holders are not required to have wearable fitness technology or have a smartphone to be insured, the company said. Instead, users will only share data they want with the company — including their physical activity, nutrition habits, gym usage or doctor's appointments. Policyholders can track everything in an app to accumulate points.

Timing: Hancock will begin converting existing life insurance policies to Vitality in 2019.