look at a commercial sleeping bag's rating, and you are looking at one inside a tent. The tent is equal to the outermost wind or rain barrier clothing.
A tarp can provide same, with more heat loss even if the wind doesn't change or natural features are available to increase efficiency. A tarp also affords a ready view of your surroundings. That's nice if you're filming a nature program or keeping an eye out for pagan biker gangs.
All systems require a piece of Mother Nature to secure the things; branches,ground,trees.There are places such as the tundra or slick rock where that can be problematical short of a mongolian yurt or bivy bag.
And time in deployment may be an issue.
The biggest issue however is simply preconceived ideas based on other's opinions that are mislabeled 'experience.'
Is Bear experienced? Yes, if breaking your neck is a reasonable way of doing things. But that's just my 'opinion' like using tarps v s tents.