The Essential plan from Nationwide Mutual Insurance is for travelers planning trips on a budget who don't want to sacrifice coverage. Coverages include Trip Cancellation and Interruption, Medical, Emergency Medical Evacuation, and Assistance Services.
To learn more, see the Nationwide Essential trip insurance product page.
Travel insurance is similar to Home Owner's insurance, premium is paid to protect your investment against potential perils. However, typically there is no discount for not having damage to your home- much the same as travel insurance cannot be discounted for not having to cancel your trip.
For comprehensive policies, premium is calculated based on: the trip cost, the length of travel, and the age of the traveler. The policy you purchased, appears to have covered pre-existing medical conditions at no additional cost, since you purchased within 10 days of making the initial trip payment.
Please let us know if you have any questions or need anything further.