Various holo sights are heavily used in Europe on double rifles for driven game shooting. I would imagine there are more 7x65rs, 8x57rs and 9.3x74rs with holosights being used today than classic open sighted doubles.

Trijicons in particular are highly regarded for driven shooting. I toyed a few years ago with mounting one on a 9.3 for this purpose. I wouldn't put in on a classic/vintage rifle, but for a modern gun in a medium caliber I think its a handy and practical combination.

I know this is not a Trijicon in the photo but it gives an idea.