There are those that claim they can't shoot a gun well without one. But, I think those folks are fooling themselves.

I had a Ithaca 37 in 16 gauge that had one. I now have an Ithaca 16 without. Can't say it made a difference to me either way, excepting the without gun cost less.

On a double, I've never owned a ventilated rib-swamped, raised, wide, and have seen a ribless design, but no ventilated.

And, I have to agree, I can't see a need for a ventilated rib on a double.
Best,
Ted