We are not too sure about doing animation that way yet. First it’s problematic both from a memory and cpu perspective. Second some animators frown upon it for how it makes rigs and moving vertices much harder to backtrack. Third, in the cases you need only one vertex to move, you can always solve it through a bone being 100% bound to that vertex only. In order to implement that feature, we need to be convinced it’s actually a good idea first and that hasn’t happened yet. 