Does this dry to a smooth finish, or is it powdery?

Smooth. Can be painted, you could likely mix in color. Material is bright white. Easy to use.

It dries to a smooth finish. If you are filling a large area and you don't have a putty knife that will bridge the gap. With any filler you need to be able to bridge across or you will not or at least have problems making flat. It's like working with icing on a cake.

This is best for filling small holes. I don't think you'll get the plaster look with this lightweight product. t works best when it is sanded smooth and painted over.

yes you can paint this product. I used a primer then paint.