I agree with what some of people here already said. Its ok until you abuse it ...
I think it just comes down to whether or not you've exhausted tracing as a learning resource. If your friend is already excellent at tracing, move on. Like any comfort zone, it's dangerous for an artist to pigeonhole themselves in one practice forever. They'll never grow.
^----Or can have the stigma of being a copycat for tracing. I have traced in a time or two but I never claimed credit for the bits I have traced. So I agree with everyone else on that it's a learning resource that really shouldn't be used too often (unless someone really needs it to help themselves).
Sometimes I trace my own work, it's pretty handy.
The important distinction here is using tracing as a technical exercise vs using it as an artisitc creation. Straight up tracing other people's images is ok if you are doing it for technical practice but I don't think you can call just copying someone's work being artistic. Tracing is more like doing craft, like a paint by numers. You end up with a nice looking end piece but it takes almost no actual artistic ability