It’s confining for the infant, who isn’t even capable of appreciating the experience, and work for the adults.
We were extremely involved parents, but I would never want to drag an infant along on a cruise.
Honestly, I don’t know why I would have to explain this. It’s common sense.
My father loved boats and took our family out on his cabin cruisers into the Chesapeake Bay. Worked fine for our family of 11, even when one of us was still in diapers.