Does the Honor Opener actually work?

When I kill a barbarian...I never gain any culture even though the little purple 7 appears after I win.

My amount of culture never changes.

It does work. I believe that culture gained via honor is added to the culture gained at the start of the next turn rather than updating immediately.

I thought that too but nope. It doesn't.

It worked long time ago when I tried such strategy. It was added right after killing the bard and there was a small animation of the floating violet +X next to the defeated unit (with some delay though).

It does work. The culture is added as soon as combat is initiated (the computer knows how the combat turns out long before the animation is displayed). Next time, note how much culture you have before you initiate combat, then check as soon as the combat is initiated. The culture counter at the top of the screen should update well before you see the purple +4 or +7 (or whatever) culture "ghost" above the combat tile.

yeah it looks like the culture is added the instant you initiate the combat (if it will result in a victory) so if you don't check your culture at the start of your turn you won't notice the change.

I read online that if you turn off combat animations...your brain will pick it up easier because the purple floating number animation and the culture change will occur at the same time on your screen.