I have learned that ... no placement is ever ideal for a profoundly gifted child ... If the child is only a few grade levels ahead, outgoing, and wants to be with older kids a grade skip is wonderful.
I have a more introverted child who is short for his age and we never considered a grade skip because a) our son didn't want it and b) he would have been very much out of place in the next two grade levels as well. Being the youngest AND academically furthest ahead is a difficult place to be and requires confidence and a thick skin ...
If you have a child who learns with 1-2 repetitions it doesn't matter where you place him - academically they'll pull ahead because schools move at a slower pace. The question is if they prefer being with older kids and can handle the move socially. Some gifted kids want to be with older peers and some don't.
A grade skip won't fix the academic gap - it is not as if they will eventually level out and start learning at a slower pace. It can help some children but is not a " one size fits all" approach ...