Can brushes for oil and acrylic painting be used for watercolor and vice versa?
Sure. You can use whatever gets you the effect you are looking for. It isn’t always easy to clean your brushes up after switching between mediums but it is your choice to do it or not. I don’t like the brushes specified for acrylic and use whatever works. Sometimes house painting brushes, pin striping brushes, sticks, q-tips, etc.