Professional artists are using reference more often than not but some use it more than others. Some professional artists use reference only as a way to develop their ability to draw or paint but avoid using reference directly when they are creating an original piece.

Is it okay to always use references in art?

No. But as an artist, you need to realize that using reference can become a crutch that you lean on too heavily. If you are trying to create an illustration that is an exact copy of a photograph, then using a reference to do so is fine.

Is referencing in art bad?

So in short, no, reference isn't bad. Artists have been using reference since the days of the old masters. They would reference life, whether it be landscapes, objects on a table, or models standing in a studio. They would even reference their own sketches or other people's work in order create convincing paintings.