actually Paint in smoke on mac is a separate module - no softfx, as you mean.
there you have "Canvas", which paints directly on an individual frame,
or "graphics", which are vectors & can be rendered over the sequence
in "Canvas" you also have an "Autopaint > User" option, where you can record a paintstroke/s an render it over a defined duration (by a second timeline)
batch-paint is not available due to lack of batch ...