If you hunt enough you'll forget to flip a safety and hear a click. You'll also forget to chamber a round, or potentially short stroke. You'll step on a stick and hear it crack. You'll be winded by the animal. You'll even have the dnr walk up and ruin a Turkey strut if you hunt long enough.
I watched many great animals not present an ethical shit and had to watch them walk away as well.
Bottom line for me, optics and the hunt cost a lot of money. I want my scopes lenses in the best condition for they shot. Even the best coatings get worn down with repeated dirt, dust, and water. If you need to clean your lenses in a hurry you'll probably use your shirt which is a big no no in optics.
For me, after hunting a very long time, what's solved that issue and protected my glass was flip covers. As I said, if you practice with them, it's just second nature.
To the OP, the o ly hunt I would not use flip covers on is DG. My life is obviously more valuable to me than a scope.