For map models, no. I tried vertex animations to handle the metal ramp deforming in the snowycoast explosion but ended up having to rig it with bones (the rest of the stuff is just a baked physics sim). I don't remember specifics, but I think it was because there was no way to trigger or intiate a vertex simulation on map props, not that you couldn't save them with the dynamic prop, but don't hold me to that.
For cosmetics, yes. You can have those flex with character expressions. Try this for reference: