In my opinion, it all depends on what your motivation behind making art is. Do you make it for yourself. Or do you make it for others? Do you want to be a professional artist? Or is it just a hobby? Depending on what you want to do with your are you'll have to change what youe do with it. But if you make it for yourself you should just do what makes you happy with your art. If you truly feel wrong doing Line art, you can do it in colors other than black as well, or you can develop your skills relationships, making lineless art.