Tracing.

Nothing inherently wrong with it.
Tracing allows you to develop skills and styles that you might not be able to obtain at any sort of pace acceptable for personal development. I do not understand why, however, that if you trace someone else's work that you do not give them due credit.

I do not mind anyone using my work for personal development as long as they accept that it is not theirs. I have run into a few incidents so far already and it is unfortunate. I am not insulted or worried, just baffled that someone would want to try and claim a piece as their own when it is not. What is the fun in that?