I am not sure I would put airfare automatically in the "non-refundable" category, unless you definition is a cash refund in total. Most "non-refundable" airline tickets are not useless and a loss if you need to change plans, since the pandemic, most of the larger airlines dropped change fees, so you can rebook dates, and many will cancel an itinerary for a credit with the airline.
I typically have little use for trip insurance for travel costs, but trip insurance to cover disruptions, medical, evacuation, that does have more value to me.
Unfortunately many companies try to sell a package based on total cost of the trip, which, for me, would mean a grossly overpriced package, and benefits I would not be able to claim, even if I incurred a total cancellation just before, or during, the trip.