I understand the lattice modifier is for deforming complex objects and it's actually pretty amazing. But the more I think about it, all the fine details can be done through sculpting shape keys. Lattice seems to have static squares which you can scale infinitely to refine your detail, but I can't think of any reason to use it over just sculpting what I want in using shape keys.
My brain is probably not seeing the big picture here... I'm mainly just focused on characters organic stuff. Even if I wanted a bicep to expand, I can do it better with shape keys.