JW funerals are rare here in Minnesota. They're mostly memorial services in Kingdom Hall, with a "reception" (cake and coffee) held at a separate banquet facility.
I don't know how the "reception" tradition started. Maybe people wanted to talk about the deceased friend or relative, something which certainly didn't occur at the memorial service.
It seems to me like the memorial service was a combination sermon and social gathering. Not very many tears are shed, for that would be "carrying on like those who have no hope".