I, too, have pondered this. I think but do not know that an insurance company would want to see cash out of pocket for valuing the loss. By that, I think they would need to see the initial expenditure. And if it is points, I fear they would not see that as an expenditure. I do try to be careful to use credit cards with travel insurance to pay the associated fees for the award booking.
What I have purchased is medical evacuation insurance. It is an annual policy. We go to some remote corners of the world. If we are in an accident, I want to be returned to my home town for care. A friend had a severe heart issue while at the company office in Delhi. It cost the company $500K to medically evacuate her and bring her to the US. I'm happy to pay my $300 policy and hope I never need to use it to avoid that kind of financial risk.
I have booked this for international travel for some of the medical/other travel benefits (we have 2 kids). I do realize that most of these benefits are duplicative of some credit card coverage. Generally most things we book with points our refundable (e.g. Hotels, Southwest, etc.) - so I generally plan that I can cancel. For other flights (e.g. AA/United/Delta) - I assume they would cover the cancellation fee (so if I spend 60K Points and there's a $200 Cancellation Fee) - I would assume I would get reimbursed for $800 ($200 tickets x4). I would assume there is no cash value for the 60K Points at all.
I always buy full trip insurance due to the medical coverage which can pay for itself. People don't realize many doctors in places around the world only accept cash, plus you have the taxi cost to get there and back (also covered) and US senior citizens can not count on Medicare out of the country. I've gotten reimbursed for trip delays, an extra night in a nice lux hotel and better flights as well as medical. The credit card coverage is limited. And, I always travel on points including hotels, but sometimes use other cc reward cash back to pay for upgrades (that's non-refundable when prepaying to get the better rooms). For 2 of us, we usually place the value around $4500 to $5000 for a 2 week trip if prepaid upgrades are involved. I also get the best plan (lux) which covers pre-existing conditions. I use CSA. I have another claim I have to submit from my recent trip, so we'll see how they are compared to my previous experience with them. They are owned by a European company, and have worked hard to evacuate travelers out of bad areas.