There was a time (decades ago) when a travel agent would upsell you travel accident insurance when you booked an airline ticket with them. Those days are now long gone as credit card networks like Visa and MasterCard have taken over that role.
Here is how it works. When you purchase an airline ticket (or any ticket like a Cruise Ticket) with this card, you will be covered for travel accident insurance of up to $250,000. The coverage is for you and any eligible dependents (like you kids) as long as you pay for their tickets as well. There are some specific terms and fine prints that go with the coverage. If you read it carefully, you will find that the phrase "common carrier" is used. This refers to airplanes, trains, cruises etc. The coverage of this benefit will start from the point of departure (most likely airport, port or train stations) and ends at the port of arrival.
Furthermore if you book a transport to the airport, train station of any terminal and it is paid before hand, the coverage will also cover that part of the trip (ie transportation to and from the port of departure and arrival).
There are also specific definitions of "travel accidents". Death is obviously considered "an event" that will trigger this policy. But aside from that, other events that will trigger this policy are the loss of limbs, eyesight etc (best to read the actual policy benefit which you will get when your card arrives).
Lost Baggage Insurance - Aside from travel accident insurance, this card also offers lost luggage insurance. While this may seem trivial, luggages do get misplaced. Fortunately, United and Continental are not the worst offenders (they are in the middle of the pack). But it is still nice to have this perk and insurance benefit. You can claim up to $3,000 ($2,000 for New York Residents) if you luggage gets lost because of theft or due to misdirection.
Travel and Emergency Service - Another perk that comes with this card is the travel and emergency service. Should you encounter an emergency when you travel abroad, there is a number which you can call and you will be provided help in various ways. For example, if you need legal assistance, Visa will help connect you with an attorney in the country which you are in. If you need medical assistance, Visa will help you to make arrangements (this can come in handy because of language barriers). There is no charges to use the service though you do have to pay for the services that you were referred to.
Roadside Assistance - Should your car or vehicle breakdown and you cannot fix the problem on your own, this card also offers roadside assistance. The number to call is 1800-VISA-TOW. There is a $59.95 per service call charge and it includes services like towing, battery charge, tire changing, lockout service and fuel delivery.