1. Art is an expression of creativity. You can draw sculpt paint and many other things. Or can be whatever you want. Or can also be an expression of your feelings.
2. An artist might need to use observation to try or paint something around the school or your neighborhood. By observing something before you draw it you can absorb the full aspect of the scene. By observing something before you draw it and while you are drawing it you can get every little detail
3. Copying is only plagiarism if you copy someone's work exactly and say it is your work. I do not think it is plagiarism if you copy someone's work or only a part of it and put your own spin on it. Or you could only copy a part of it and draw the rest. Or use the same style. I think that is copying but not plagiarism.
4. Art can be a form of relaxation. Some people use it to calm down. Other people may use it to express their feelings. Most people just do art for fun but you can do it for any reason.
At the beginning of the year I was trying buddies with bad ratios and trying to draw things without looking at them. Now I try to observe things before I draw them. I also like to experiment with new mediums